WO2008147132A1

WO2008147132A1 - Horn array type antenna for dual linear polarization

Info

Publication number: WO2008147132A1
Application number: PCT/KR2008/003036
Authority: WO
Inventors: Seung Joon Im; Chang Wan Ryu; Jae Ho Ko
Original assignee: IDOIT CO Ltd
Current assignee: IDOIT CO Ltd
Priority date: 2007-06-01
Filing date: 2008-05-30
Publication date: 2008-12-04
Anticipated expiration: 2009-12-01
Also published as: KR20080105856A

Abstract

The present invention relates to a horn array antenna for dual linear polarization, including a horn which guides incoming or outgoing electromagnetic waves, a rib which is connected to an upper portion of the horn and divides an opening of the horn into a plurality of openings, a first polarization guide which is connected to one end of the horn and has a plurality of passages arranged adjacent to one another for guiding first polarizations, and a second polarization guide which is connected to one end of the horn and is arranged in parallel to the first polarization guide, for guiding second polarizations having an electric field directivity perpendicular to the first polarizations.

Description

HORN ARRAY TYPE ANTENNA FOR DUAL LINEAR

POLARIZATION

Technical Field

[1] The present invention relates to a horn array type antenna for dual linear polarization, and more particularly, a horn array type antenna for dual linear polarization for improving an antenna performance and reducing a size of the antenna. Background Art

[2] Waves traveling higher than ultrahigh frequency have very short wavelengths and have characteristics similar to light. In order to effectively receive and transmit such waves, the technology has advanced itself to improve the directivity, applying optics theory or the theory that says a megaphone concentrates a sound wave. Such antennas, with enhanced directivity, are known as horn antenna, parabola antenna, lens antenna, and slot antenna which have waveguides with holes formed thereon.

[3] Among these, the horn antenna is formed of a waveguide with one end formed in a horn shape and opened at both ends. The horn antenna propagates electromagnetic waves along the waveguide by vibrating one end of the waveguide so as to radiate to the air. As the impedance between the waveguide and the air is not matching, it reflects a part of the electromagnetic wave, which means that the entire energy is not radiated to the air. Therefore, a horn antenna is designed to have its waveguide opening to be gradually wider so that it matches the impedance between the air and the waveguide and allows it to maximally radiate energy through the opening.

[4] FIG. 1 is a cross-sectional view of a horn in a general horn antenna.

[5] As shown in the drawing, the horn antenna shows an outer opening 2 facing the air, and an inner opening 3 at a side where the vibration starts. In such an antenna, the size of the outer opening 3 decides the performance of the antenna. The wider the size of the outer opening 3 is, the better the performance is provided. A ratio (S /S ) of the size of the outer opening 2 and that of the inner opening 3 influences the performance of the antenna. The ratio (S /S ) of the size of the outer opening 2 and the inner

2 1 opening 3, i.e., the difference between the size of the outer opening 2 and that of the inner opening 3 and the gradient of the horn are important factors that decide the performance. Therefore, the horn should be longer and accordingly the overall size of the antenna should be larger. [6] The present trend of the development of communication technology is towards compactness. Therefore, it is a main issue in designing an antenna that the size of the antenna is minimized.

[7] Accordingly, there is a need for a method that can reduce the size of antenna, while improving, or at least sustaining its performance. Disclosure of Invention Technical Problem

[8] Therefore, an object of the present invention is to provide a horn array antenna for dual linear polarization having an improved antenna performance and a small size. Technical Solution

[9] The above object is achieved by providing a horn array antenna for dual linear polarization. The horn array antenna for dual linear polarization is characterized of including a horn which guides incoming or outgoing electromagnetic waves, a rib which is connected to an upper portion of the horn and divides an opening of the horn into a plurality of openings, a first polarization guide which is connected to one end of the horn and has a plurality of passages arranged adjacent to one another for guiding first polarizations, and a second polarization guide which is connected to one end of the horn and is arranged in parallel to the first polarization guide, for guiding second polarizations having an electric field directivity perpendicular to the first polarizations.

[10] Preferably, the rib includes first ribs which are arranged in a vertical direction and a horizontal direction with a predetermined gap thereamong in a lattice pattern, and second ribs which have a width narrower than that of the first ribs and are formed between the first ribs and the horn.

[11] The first ribs and the second ribs may be integrally formed with each other.

[12] The above object is also achieved by a horn array antenna for dual linear polarization, characterized of including a third layer where a horn for guiding incoming or outgoing electromagnetic waves is formed, a first layer and a second layer which are connected with an upper portion of the horn and form a rib which divides an opening of the horn into a plurality of openings, a plurality of fourth layers which are connected to one end of the horn and form a first polarization guide which has a plurality of passages formed adjacent to one other, for guiding first polarizations, and a plurality of fifth layers which are connected to one end of the horn and form a second polarization guide which is arranged in parallel to the first polarization guide, for guiding second polarizations having an electric field directivity perpendicular to the first polarizations. [13] Preferably, the first layer forms first ribs of the rib which are arranged in a vertical direction and a horizontal direction with a predetermined gap thereamong in a lattice pattern, and the second layer forms second ribs which have a width narrower than that of the first ribs and are arranged between the first ribs and the horn.

[14] The first layer and the second layer may be integrally formed with each other.

[15] The horn array antenna for dual linear polarization may further include at least one sjmmetrical branch tube which connects the first polarization guide or the second polarization guide in the ratio of 1:1, and at least one asjmmetrical branch tube which connects the first polarization guide or the second polarization guide in the ratio of l:n.

[16] The asjmmetrical branch tube may have a port 1 and a port 2 which face each other and a port 3 which is arranged in a perpendicular relation to the port 1 and the port 2, and a port 1 tube connected to the port 1 and a port 2 tube connected to the port 2 may be bent in a substantially " π " shape.

[17] The port 1 tube and the port 2 tube may be formed such that their areas connected to the port 3 are layered one on the other in a vertical direction.

[18] The port 1 tube and the port 2 tube may differ from each other in their heights.

[19] The port 1 tube and the port 2 tube each may have a plurality of steps formed therein and gradually becoming lower in their heights toward the port 3, and the number of steps formed in the port 1 tube and the port 2 tube may differ from each other.

[20] The port 1 tube and the port 2 tube each may have a plurality of steps formed therein and gradually becoming lower in their heights toward the port 3, and heights and widths of the steps formed in the port 1 tube and the port 2 tube may differ from each other.

[21] A port 3 tube connected to the port 3 may have a narrow width at an area connected to the port 1 tube and the port 2 tube.

Advantageous Effects

[22] As described above, according to the present invention, the performance of the antenna can be improved while the size of the antenna is reduced.

[23] Also, while the invention has been shown and described with reference to certain detail embodiments thereof, it will be understood by those skilled in the art that they are merely exemplary and various changes may be made therein without departing from the technical idea of the invention. Therefore, the scope of the present invention is not limited to the described embodiment and should be defined by the appended claims and the full scope of equivalents thereof. Brief Description of the Drawings

[24] FIG. 1 is a cross-sectional view of a horn in a general horn antenna,

[25] FIG. 2 is a top view of a horn array antenna for dual linear polarization according to an exemplary embodiment of the present invention, [26] FIG. 3 is a transparent perspective view of the horn of the horn array antenna for dual linear polarization according to the exemplary embodiment of the present invention, [27] FIG. 4 is a partially-cut perspective view of the horn of FIG. 3,

[28] FIG. 5 is a partially cut transparent perspective view of the horn of FIG. 3,

[29] FIG. 6 is a side view of the horn according to an exemplary embodiment of the present invention, [30] FIG. 7 is a side view of a horn which has an outer opening of the same size as that of the horn of FIG. 6 and has the same length as that of the horn of FIG. 6, [31] FIG. 8 is a side view of a horn which has the same performance as that of the horn of

FIG. 6

[32] FIG. 9 is a graph illustrating a parameter Sl 1 of the horn of FIG. 6,

[33] FIG. 10 is a graph illustrating a parameter Sl 1 of the horn of FIG. 7,

[34] FIG. 11 is a graph illustrating a parameter Sl 1 of the horn of FIG. 8

[35] FIG. 12 is a perspective view of the first polarization guide and the second polarization guide of FIG. 2 in an assembled state, [36] FIG. 13 is a top view of the first polarization guide and the second polarization guide of FIG. 2 in the assembled state, [37] FIG. 14 is a bottom view of the first polarization guide and the second polarization guide of FIG. 2 in the assembled state,

[38] FIG. 15 is a perspective view of the first polarization guide of FIG. 2,

[39] FIG. 16 is a transparent perspective view of the first polarization guide of FIG. 2,

[40] FIG. 17 is a top view of the first polarization guide of FIG. 2,

[41] FIG. 18 is a bottom view of the first polarization guide of FIG. 2,

[42] FIG. 19 is a perspective view of the second polarization guide of FIG. 2,

[43] FIG. 20 is a transparent perspective view of the second polarization guide of FIG. 2,

[44] FIG. 21 is a top view of the second polarization guide of FIG. 2,

[45] FIG. 22 is a bottom view of the second polarization guide of FIG. 2,

[46] FIG. 23 is a perspective view of a T-shaped branch tube according to an exemplary embodiment of the present invention, [47] FIG. 24 is a perspective view of a T-shaped branch tube according to another exemplary embodiment of the present invention, [48] FIG. 25 is an exploded perspective view illustrating layers of the horn array antenna for dual linear polarization in the unit of antenna according to the exemplary embodiment of the present invention,

[49] FIG. 26 is a perspective view of the 1st layer of FIG. 24,

[50] FIG. 27 is a perspective view of the 2nd layer of FIG. 24,

[51] FIG. 28 is a perspective view of a 1st layer and a 2nd layer according to another exemplary embodiment of the present invention, [52] FIG. 29 is a transparent perspective view of the 1st layer and the 2nd layer of FIG.

28,

[53] FIG. 30 is a bottom view of the 1st layer and the 2nd layer of FIG. 28,

[54] FIG. 31 is a top view of the 3rd layer of FIG. 24,

[55] FIG. 32 is a perspective view of the 3rd layer of FIG. 24,

[56] FIG. 33 is a top view of the 4th- 1 layer of FIG. 24,

[57] FIG. 34 is a bottom view of the 4th- 1 layer of FIG. 24,

[58] FIG. 35 is a transparent perspective view of the 4th- 1 layer of FIG. 24,

[59] FIG. 36 is a top view of the 4th-2 layer of FIG. 24,

[60] FIG. 37 is a bottom view of the 4th-2 layer of FIG. 24,

[61] FIG. 38 is a perspective view of the 4th-2 layer of FIG. 24,

[62] FIG. 39 is a top view of the 4th-3 layer of FIG. 24,

[63] FIG. 40 is a bottom view of the 4th-3 layer of FIG. 24,

[64] FIG. 41 is a transparent perspective view of the 4th-3 layer of FIG. 24,

[65] FIG. 42 is a top view of the 4th-4 layer of FIG. 24,

[66] FIG. 43 is a bottom view of the 4th-4 layer of FIG. 24,

[67] FIG. 44 is a perspective view of the 4th-4 layer of FIG. 24,

[68] FIG. 45 is a top view of the 5th- 1 layer of FIG. 24,

[69] FIG. 46 is a bottom view of the 5th- 1 layer of FIG. 24,

[70] FIG. 47 is a transparent perspective view of the 5th- 1 layer of FIG. 24,

[71] FIG. 48 is a transparent perspective view of the 5th-2 layer of FIG. 24,

[72] FIG. 49 is a front perspective view illustrating an example of the use of the horn array antenna for dual linear polarization according to the exemplary embodiment of the present invention,

[73] FIG. 50 is a side view of the antenna of FIG. 49,

[74] FIG. 51 is a bottom view of the antenna of FIG. 49,

[75] FIG. 52 (a) to (c) are a top view, a perspective view and a transparent perspective view of the asjmmetrical branch tube of FIG. 51, respectively. [76] FIG. 53 (a) to (c) are a top view, a perspective view, and a transparent perspective view of the asjmmetrical branch tube of FIG. 51 according to another exemplary embodiment, respectively, and

[77] FIG. 54 (a) to (c) are a top view, a perspective view, and a transparent perspective view of the asjmmetrical branch tube of FIG. 51 according to still another exemplary embodiment of the present invention.

[78] <Description of Signs for Main Parts of the Drawings>

[79] 1: antenna 10: horn

[80] 15: inclined part 17:ledge

[81] 20: polarization filtering unit 21: protruding rib

[82] 23: first step 25: second step

[83] 30: first polarization guide 35: first waveguide

[84] 40: second waveguide 45: first mixing tube

[85] 50: second polarization guide 55: third waveguide

[86] 60: fourth waveguide 65: second nixing tube

[87] 70: first rib 75: second rib

[88] 100: first layer 150: second layer

[89] 200: third layer 250: 4th- 1 layer

[90] 300: 4th-2 layer 350: 4th-3 layer

[91 ] 400: 4th-4 layer 450: 5th- 1 layer

[92] 500: 5th-2 layer

Best Mode for Carrying Out the Invention

[93] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[94] A horn array antenna for dual linear polarization according to an exemplary embodiment of the present invention performs a function of either receiving or transmitting electromagnetic waves. However, for the convenience of explanation, descriptions will be made about elements of the horn array antenna for dual linear polarization with reference to the function of receiving electromagnetic waves at first, and then, the function of transmitting the electromagnetic waves will be described.

[95] According to an exemplary embodiment of the present invention, a first polarization denotes a horizontal polarization (H polarization) parallel to the equator of earth, and a second polarization denotes a vertical polarization (V polarization) which is perpendicular to the equator of earth.

[96] FIG. 2 is a perspective view of a horn array antenna for dual linear polarization according to an exemplary embodiment of the present invention.

[97] A horn array antenna 1 for dual linear polarization according to an exemplary embodiment of the present invention includes a plurality of horns 10 through which electromagnetic waves enter, a first rib 70 and a second rib 80 which are mounted to upper portions of the horns 10 in a lattice pattern, a first polarization guide 30 for guiding first polarizations of the electromagnetic waves incident through the horns 10, and a second polarization guide 50 for guiding second polarizations of the electromagnetic waves incident through the horns 10.

[98] The horns 10 are opened to the air, and the single first polarization guide 30 is formed under the four (4) horns 10 and the second polarization guide 50 is formed under the first polarization guide 30. The horns 10 and the first and the second polarization guides 30, 50 provide a space where the electromagnetic waves travel. Layers for forming the horns 10 and the first and the second polarization guides 30, 50 will be described below.

[99] In the horn array antenna for dual linear polarization according to the present invention, the four (4) horns 10, the single first polarization guide 30, and the single second polarization guide 50 form a single antenna unit, and hereinafter, the horn array antenna 1 for dual liner polarization will be described with reference to this antenna unit

[100] FIG. 3 is a transparent perspective view of the horn of the horn array antenna for dual linear polarization according to the exemplary embodiment of the present invention, FIG. 4 is a partially-cut perspective view of the horn of FIG. 3, and FIG. 5 is a partially cut transparent perspective view of the horn of FIG. 3.

[101] The first and second ribs 70, 75 are mounted on the top of the horn 10 in a manner that the second rib 75 is seated on an outer opening of the horn 10 and the first rib 70 is seated on the top surface of the second rib 75. The first and the second ribs 70, 75 are formed in a lattice pattern such that the respective component ribs are arranged with a predetermined distance apart away from one another. The component ribs forming the first rib 70 and the second rib 75 and the component ribs forming the second rib 75 are arranged at the same locations.

[102] The first rib 70 has a width along a plane direction of the outer openings of the horns 10, which is wider than a height along a penetrating direction of the outer openings, and the second rib 75 has a width along a plane direction, which is narrower than a height along a penetrating direction.

[103] The first rib 70 and the second rib 75 are arranged in a crisscross pattern with respect to the outer opening of the one horn 10, and the outer opening of the horn 10 is divided into four openings by the first rib 70 and the second rib 75. As a single antenna unit includes four (4) horns 10 and the outer opening of each of the horns 10 is divided into four openings by the first and the second ribs 70, 75, the sixteen (16) openings are formed on the single antenna unit.

[104] If the outer opening of each of the horns 10 is divided into a plurality of openings, a sidelobe of the antenna is reduced and radiation efficiency is improved.

[105] The horn 10 guides electromagnetic waves such that first polarizations and second polarizations having a perpendicular direction on an incident surface are incident, and includes an inclined part 15 having a quadrangular pyramid shape and a polarization filter unit 20 formed at one side end of the inclined part 15.

[106] The inclined part 15 is tapered along an advancing direction of the electromagnetic waves and has open opposite ends along the advancing direction of the electromagnetic waves. One of the open opposite ends of the inclined part 15 that is toward the first and the second ribs 70, 75 is referred to as an outer opening, and the other one that is formed at a narrower inner end of the inclined part 15 is referred to as an inner opening. The inner opening has a ledge 17 protruding from an edge thereof toward a center and the ledge 17 protrudes around the inner opening by a predetermined width.

[107] A pair of protruding guides 18a, 18b is formed along an inner surface of the inclined part 15. The pair of protruding guides 18a, 18b is formed along an inner surface of the inclined part 15 in a circumference direction with a gap therebetween. The at least one protruding guides 18 a, 18b allows for improvement of the antenna performance of the horn array antenna and for reduction in the height of the horn array antenna.

[108] If the ledge 17 and the protruding guides 18a, 18b are formed on the inner opening of the inclined part 15 as described above, it is possible to reduce the length of the inclined part 15 without changing the widths of the inner opening and the outer opening, and also it is possible to maintain a gain of the antenna 1.

[109] Although the inclined part 15 has the two protruding guides 18a, 18b, this is merely an example and the number of the protruding guides 18a, 18b is variable.

[110] The horn array antennal for dual linear polarization shown in FIG. 2 employs the horn shown in FIG. 3 but it is natural the any other size or shape horn is employed.

[I l l] FIG. 6 is a side view of the horn according to the exemplary embodiment of the present invention, FIG. 7 is a side view of a conventional horn which has an outer opening of the same size as that of the horn of FIG. 6 and has the same length as that of the horn of FIG. 6, and FIG. 8 is a side view of a conventional horn which has the same performance as that of the horn of FIG. 6.

[112] The horn of FIG. 6 is the same as the horn 10 of FIGS. 3 to 5 in that it has the ledge 17 protruding from the inner opening of the inclined part 15 to the center, but it removes the protruding guides 18a, 18b from the inclined part 15 for the sake of simplicity.

[113] The horn shown in FIGS. 6 and 7 has a length of 61.0mm and the horn shown in FIG. 8 has a length of 71.0mm. The horns shown in FIGS. 6 to 8 have the same width of the outer opening of 48.0mm.

[114] The antenna gains obtained by the three horns at a central frequency 11.7GHz, an upper sideband of 12.57GHz, and a lower sideband of 10.7GHz, all of which belong to a satellite broadcast band (KU band) from 10.7GHz to 12.75GHz, are represented in following table 1.

[115] Table 1 [Table 1] [Table ]

[116] As seen from the above table, the horn 10 of FIG. 6 according to the present invention and the horn of FIG. 8 show the same performance at all the frequency bands. However, the horn of FIG. 7 which has the same length and the same size outer opening as those of the horn 10 of the present invention has antenna gains which are smaller than those of the horn 10 of the present invention by 0.5dBi at 10.7GHz, by 0,7dBi at 11.7GHz, and by 0.5dBi at 12.7GHz. If a difference in the antenna gain is IdBi, generally, the performance can be regarded as being improved by 33%. Therefore, the horn 10 according to the present invention improves the antenna performance by 18% compared to the conventional horn having the same size. Also, it is possible to reduce the height by 10mm compared to the horn having the same performance.

[117] FIG. 9 is a graph illustrating a parameter Sl 1 of the horn of FIG. 6, FIG. 10 is a graph illustrating a parameter Sl 1 of the horn of FIG. 7, and FIG. 11 is a graph a parameter S 11 of the horn of FIG. 8. [118] The parameter SI l indicates the degree by which the electromagnetic waves emitted from the antenna are sent back to the antenna. Less the parameter SI l, the better the antenna performance is provided. In general, an allowable range of the parameter SI l is less or equal to -1OdB.

[119] As shown in the drawings, as the horn 10 of the present invention indicates the parameter Sl 1 of -4OdB at 11.6GHz, the parameter SI l can be regarded as being good. This good result is evident if it is compared to the horn of FIG. 7 showing the parameter SI l of-50dB at 12.2GHz and the horn of FIG.8 showing the parameter SI l of -3OdB at HGHz.

[120] If the ledge 17 is formed on the inner opening of the inclined part 15 as described above, it is possible to reduce the length of the inclined part 15 without changing the widths of the inner opening and the outer opening and also the antenna gain is not reduced.

[121] The polarization filtering unit 20 is connected to the inner opening of the inclined part 15 and four (4) polarization filtering units 20 are provided for a single antenna unit. Each of the polarization filtering units 20 passes only specific polarizations of the electromagnetic waves incident through the horns 10, i.e., passes only second polarizations and does not pass first polarizations.

[122] The polarization filtering unit 20 has an opening formed on one of inside surfaces thereof and fluidly communicating with the first polarization guide 30. A lower end of the opening further protrudes toward the inside of the polarization filtering unit 20 than an upper end of the opening such that a first step 23 is formed. A pair of shielding screens 11, which has a vertically elongated plate shape, is formed at opposite sides of an entrance of the opening and is spaced from each other by a predetermined distance. A vertically elongated slot 13 is formed between the shielding screens 11. From a conjunction area between the shielding screens 11, a split plate 37 protrudes forwardly by a predetermined length on one hand and extends backwardly on the other hand. The split plate 37 is wider than the shielding screens 11 by a predetermined width. The shielding screens 11 each has an "L" shaped bending protrusion 12 protruding from an area adjacent to the inside surface of the polarization filtering unit 20 and then upwardly bent. The bending protrusion 12 protrudes from an area of the shielding screen 11 where the split plate 37 is formed.

[123] The polarization filtering unit 20 has a second step 25 protruding from an inside surface of an area facing the lower end of the opening of the polarization filtering unit 20. Also, a protruding rib 21, which has a vertically elongated shape, is formed above the second step 25 on an area corresponding to the slot 13. Due to the presence of the protruding rib 21 and the bending protrusion 12, the parameter Sl 1 of the vertical polarization can be improved.

[124] The polarization filtering unit 20 has a width which becomes gradually narrower due to the presence of the first step 23 and the second step 25, and accordingly, the first polarizations and the second polarizations are separated from each other by the polarization filter unit 20 and are provided to the first polarization guide 30 and the second polarization guide 50, respectively. At this time, the first polarizations, which have the same electric field directivity as the wider width of the polarization filtering unit 20, do not pass the polarization filtering unit 20 and are guided to the first polarization guide 30, whereas the second polarizations, which have the same electric field directivity as the narrower width of the polarization filtering unit 20, pass through the first step 23 and the second step 25 of the polarization filtering unit 20 and are guided to the second polarization guide 50.

[125] In the above-described embodiment, the one first step 23 and the one second step 25 are formed in the polarization filtering unit 20, but the numbers of the first step 23 and the second step 25 and the dimensions and the lengths thereof are variable depending on the frequency of the second polarizations guided to the second polarization guide 50.

[126] FIG. 12 is a perspective view of the first polarization guide and the second polarization guide of FIG. 2 in an assembled state, FIG. 13 is a top view of the first polarization guide and the second polarization guide of FIG. 2 in the assembled state, and FIG. 14 is a bottom view of the first polarization guide and the second polarization guide of FIG. 2 in the assembled state.

[127] The first polarization guide 30 and the second polarization guide 50 receive the first polarizations and the second polarizations from the four (4) polarization filtering units 20, and the four (4) polarization filtering units 20 are located on the four sides of the first polarization guide 30 and the second polarization guide 50. The first polarization guide 30 has a first main opening 48 through which the first polarizations enter or exit, and the second polarization guide 50 has a second main opening 68 through which the second polarizations enter or exit. The first main opening 48 and the second main opening 68 are formed in a perpendicular relation to each other.

[128] FIG. 15 is a perspective view of the first polarization guide of FIG. 2, FIG. 16 is a transparent perspective view of the first polarization guide of FIG. 2, FIG. 17 is a top view of the first polarization guide of FIG. 2, and FIG. 18 is a bottom view of the first polarization guide of FIG. 2.

[129] The first polarization guide 30 guides the first polarizations entering through the four (4) horns 10 and emits them, and has four (4) openings formed at the four sides thereof and connected to the four (4) polarization filtering units 20.

[130] The first polarization guide 30 includes a first waveguide 35 connecting a pair of openings, a first guide tube 46 connected to a middle area of the first waveguide 35 in a bent shape, a second waveguide 40 connecting the other pair of openings, a second guide tube 47 connected to a middle area of the second waveguide 40 in a bent shape, and a first mixing tube 45 connected to ends of the first guide tube 46 and the second guide tube 47.

[131] A pair of split plates 36, 37 extending from the pair of shielding screens 11 is formed in each of the first waveguide 35 and the second waveguide 40 along a lengthwise direction of the first waveguide 35 and the second waveguide 40. One of the split plates 36, 37 formed in the first waveguide 35 that is connected to the first guide tube 46 is referred to as a first split plate 36, and the other one facing the first split plate 36 is referred to as a second split plate 37. One of the split plates 41, 42 formed in the second waveguide 40 that is connected to the second guide tube 47 is referred to as a third split plate 41, and the other one facing the third split plate 41 is referred to as a fourth split plate 42. The first through the fourth split plates 36, 37, 41, and 42 are formed in the middle areas of the first wave guide 35 and the second waveguide 40 in a vertical direction such that the first waveguide 35 is split into an upper area and a lower area by the first split plate 36 and the second split plate 37, and the second waveguide 40 is split into an upper area and a lower area by the third split plate 41 and the fourth split plate 42.

[132] The first split plate 36 and the third split plate 41 each has a cut-off part formed on a middle portion thereof in a lengthwise direction and in a substantially "τ= " shape. That is, a cut-off part formed on the first split plate 36 is referred to as a first cut-off part 38 and a cut-off part formed on the third split plate 41 is referred to as a second cut-off part 43.

[133] The second split plate 37 and the fourth split plate 42 have a first protrusion 39 and a second protrusion 44, respectively, protruding from middle portions thereof toward the first split plate 36 and the third split plate 41, and the first protrusion 39 and the second protrusion 44 are elongated in a vertical direction to connect an upper surface and a lower surface of the first waveguide 35 and the second waveguide 40.

[134] A first protruding piece 34 and a second protruding piece 49 of a rectangular paral- lelepiped shape are formed in middle areas of the first cut-off part 38 and the second cut-off part 43 and protrude toward the first protrusion 39 and the second protrusion 44. The first protruding piece 34 is formed on a lower area of the first split plate 36 and the second protruding piece 49 is formed on an upper area of the third split plate 41.

[135] The frequency of the first polarizations entering into or exiting from the first polarization guide 30 can be adjusted by varying thicknesses and lengths of the first and the second protrusions 39, 44 and widths of the first and the second cut-off parts 38, 43 and of the first and the second protruding pieces 34, 49. Also, a phase of the first polarization guided from the first waveguide 35 and the second waveguide 40 is adjusted by the first and the second protrusions 39, 44 and the first and the second protruding pieces 34, 39. That is, the first polarizations are prevented from being deformed or extinguished due to any phase difference when the first polarizations from the first guide tube 46 and the second guide tube 47 are nixed in the first nixing tube 45.

[136] The first guide tube 46 is connected to an area of the first waveguide 35 where the first split plate 36 is formed, and is bent in a substantially L "L shape. At this time, an inner edge is bent at 90° one time along a bending direction, whereas an outer edge is bent in several times. The height of the first waveguide 35 corresponds to a half of the height of the first guide tube 46. The first guide tube 46 is connected to an upper area of the first waveguide 35 and a lower surface of the first waveguide 35 is coplanar with the first split plate 36.

[137] The second guide tube 47 has the same height as that of the first guide tube 46 and is connected to an area of the second waveguide 40 where the third split plate 41 is formed and it is bent in a substantially "L" shape. Compared to the first guide tube 46, the second guide tube 47 is connected to a lower area of the second waveguide 40 and an upper surface of the second waveguide 40 is coplanar with the third split plate 41. Ends of the first guide tube 46 and the second guide tube 47 are bent in the same direction and are located one on the other. Also, sidewalls of the first guide tube 46 and the second guide tube 47 are interconnected to each other at the ends of the first and the second guide tubes 46, 47.

[138] A first nixing tube 45, which is connected to the ends of the first and the second guide tubes 46, 47, has a height corresponding to a sum of heights of the first guide tube 46 and the second guide tube 47. The first nixing tube 45 has an upper surface connected to an upper surface of the first guide tube 46 and a lower surface connected to a lower surface of the second guide tube 47. The first mixing tube 45 is a single tube so that it nixes the first polarizations traveling from the first guide tube 46 and the second guide tube 47 and emits the nixed waves through the first main opening 48.

[139] The first nixing tube 45 is larger than the first and the second guide tubes 46, 47 in view of its horizontal width and its vertical width, and at least one step is formed in a horizontal direction and at least one another step is formed in a vertical direction, both being formed along a lengthwise direction of the first nixing tube 45, such that the width of the first nixing tube 45 is enlarged. Herein, one or a plurality of steps may be formed.

[140] If the first polarizations enter from the polarization filtering units through the slot 13 of the first and the second waveguides 35, 40 of the first polarization guide, the first polarizations travel along the upper area and the lower area which are formed by the first split plate 36 and the second split plate 37 of the first waveguide 35. The first polarizations incident from the opposite ends of the first waveguide 35 meet and are nixed at the middle area of the first waveguide 35 i.e. at the first protrusion 39, and the nixed first polarizations travel toward the first guide tube 46. At this time, the first polarizations traveling around the upper areas of the first split plate 36 and the second split plate 37 moves toward the first guide tube 46 in advance, and then, the first polarizations nixed by the first cut-off part 38 formed in the middle area of the first split plate 36 are guided into the first guide tube 46, so that the first polarizations can easily move. In a similar way, the first polarizations traveling along the upper area and the lower area of the third split plate 41 and the fourth split plate 42 in the second waveguide 40 meet and are nixed at the second protrusion 44, and then are guided into the second guide tube 47 by the second cut-off part 43 so that the first polarization can easily move.

[141] The first polarizations transmitted from the first waveguide 35 and the second waveguide 40 to the first guide tube 46 and the second guide tube 47 are nixed in the first nixing tube 45.

[142] FIG. 19 is a perspective view of the second polarization guide of FIG. 2, FIG. 20 is a transparent perspective view of the second polarization guide of FIG. 2, Fig. 21 is a top view of the second polarization guide of FIG. 2, and FIG. 22 is a bottom view of the second polarization guide of FIG. 2.

[143] The second polarization guide 50 receives second polarizations separated by the polarization filtering units 20 and nixes them, and it includes a third waveguide 55 and a fourth waveguide 60 to nix the second polarizations from a pair of polarization filtering units 20, and a second nixing tube 65 connecting the third waveguide 55 and the fourth waveguide 60 to nix the second polarizations from the third waveguide 55 and the fourth waveguide 60.

[144] The third waveguide 55 and the fourth waveguide 60 each has upwardly open openings formed at opposite ends thereof and connected to the polarization filtering units 20. The third waveguide 55 and the fourth waveguide 60 are arranged in a perpendicular relation to the first and the second waveguides 35 and 40.

[145] The third waveguide 55 has first direction change protrusions 56 formed on opposite ends thereof fluidly communicating with the polarization filtering units 20. The first direction change protrusions 56 each is formed in a rectangular parallelepiped shape along a lengthwise direction of the third waveguide 55 and protrudes from the bottom of the third waveguide 55. The second polarizations, which have an electric field directivity along the narrow width of the polarization filtering unit 20, change their advancing direction at the first direction change protrusions 56. First inclined surfaces 57 are formed on surfaces facing the first direction change protrusions 56 and inclined by a predetermined angle. The second polarizations, which have changed their advancing direction at the first direction change protrusions 56, are reflected on the first inclined surfaces 57.

[146] A third protrusion 58 extending toward the second nixing tube 65 by a predetermined length is formed in a middle area of the third waveguide 55. The second polarizations reflected on the first inclined surfaces 57 at the opposite ends of the third waveguide 55 meet and are nixed at the third protrusion 58, and then advance toward the second nixing tube 65.

[147] The fourth waveguide 60 is formed in the same shape as that of the third waveguide 55. That is, the fourth waveguide 60 has second direction change protrusions 61 formed at opposite ends thereof fluidly communicating with the polarization filtering units 20. Second incline surfaces 62 are formed on surfaces facing the second direction change protrusions 61 and inclined by a predetermined angle, and a fourth protrusion 63 extending across the length of the fourth waveguide 60 to a predetermined length is formed in a middle area of the fourth waveguide 60.

[148] The second polarizations which have entered into the fourth waveguide 60 change their advancing direction at the second direction change protrusions 61, are reflected on the second inclined surfaces 62 and then advances toward the fourth protrusion 63. The second polarizations from the opposite ends of the fourth waveguide 60 meet at the fourth protrusion 63 and advance toward the second nixing tube 65. The frequency of the second polarizations which enter into or exits from the second polarization guide 50 can be adjusted according to thicknesses and lengths of the third and the fourth protrusions 58, 63 and widths and heights of the first and the second inclined surfaces 57, 62.

[149] The second nixing tube 65 is formed between the third waveguide 55 and the fourth waveguide 60 in parallel with them, and is perpendicular to the first nixing tube 45. Accordingly, the second main opening 68 formed at one end of the second nixing tube 65 is perpendicular to the first main opening 48. A fifth protrusion 66 is formed on the other end of the second nixing tube 65, facing the second main opening 68, and protrudes along the lengthwise direction of the third and the fourth waveguides 60. The second polarizations from the third and the fourth waveguides 60 meet and are nixed at the fifth protrusion 66 and then advance toward the second main opening 68 and exits therefrom.

[150] A first protruding piece 59 is formed in a conjunction area where the second nixing tube 65 and the third and the fourth waveguides 55, 60 join together and it protrudes from opposite side walls inwards to narrow a width of the conjunction area. A second protruding piece 67 is formed at a side of the second nixing tube 65 and protrudes from opposite side walls along a lengthwise direction of the second nixing tube 65.

[151] The second nixing tube 65 is able to change a frequency band of an incoming or outgoing signal according to a length and a thickness of the fifth protrusion 66, and also is able to improve antenna performance due to the presence of the first and the second protruding pieces 59, 67.

[152] FIG. 23 is a perspective view of a T-shaped branch tube according to an exemplary embodiment of the present invention.

[153] The T-shaped branch tube is applicable to a conjunction area between the first waveguide 35 and the first guide tube 46 of the first polarization guide, a conjunction area between the second waveguide 40 and the second guide tube 47, a conjunction area between the third waveguide 55 and the second nixing tube 65 of the second polarization guide 50, a conjunction area between the fourth waveguide 60 and the second nixing tube 65, and the second nixing tube 65.

[154] The T-shaped branch tube has a port 1, a port 2, and a port 3. The ports 1 and 2 are placed in a straight line and in perpendicular relation to the port 3. The ports 1 and 2 each have a step such that a width thereof becomes gradually narrower toward the port 3. A protrusion is formed between the ports 1 and 2 and protrudes toward inside a passage connecting the port 1 and the port 2. The port 3 has a step such that a width thereof becomes gradually broader toward an end of the port 3. The step formed on each of the ports 1, 2, and 3 may be a single step or a plurality of steps, and a length or a thickness of the protrusion is adjustable.

[155] FIG. 24 is a perspective view of a T-shaped branch tube according to another exemplary embodiment of the present invention.

[156] The T-shaped branch tube according to this embodiment is applicable to a conjunction area between the first waveguide 35 and the first guide tube 46 of the first polarization guide, a conjunction area between the second waveguide 40 and the second guide tube 47, a conjunction area between the third waveguide 55 and the second nixing tube 65 of the second polarization guide 50, a conjunction area between the fourth waveguide 60 and the second mixing tube 65, and the second nixing tube 65.

[157] In the T-shaped branch tube according to this embodiment, a pair of depressions 51 protrudes outwardly from a passage connecting a port 1 and a port 2 and a protrusion 53 protrudes inwardly the passage connecting the port 1 and the port 2 between the pair of depressions 51. Intercepting screen 52 protruding inwardly from opposite side walls adjacent to the port 1 and the port 2 are formed in a passage leading the port 3.

[158] Hereinafter, a process of receiving first polarizations and second polarization separately through the horn array antenna for dual linear polarization constructed above will now be described.

[159] If electromagnetic waves enter through the horns, the electromagnetic waves are guided along the inclined parts 15 and then arrive at the polarization filtering units 20 through the ledges 17. The polarization filtering units 20 each has one end becoming gradually narrower due to the presence of the first step 23 and the second step 25. Consequently, the first polarizations, which have the same electric field directivity as the wider width of the polarization filtering unit 20, do not pass through the polarization filtering units 20 and instead enter into the first polarization guide 30 through the slot 13 formed between the pair of shielding screens 11 of the polarization filtering units 20. On the other hand, the second polarizations, which have the same electric field directivity as the narrower width of the polarization filtering unit 20, move down along the polarization filtering units 20 and enter into the second polarization guide 50.

[160] Consequently, the first polarizations enter into the first and the second waveguides 35, 40 of the first polarization guide 30 from the respective polarization filtering units 20. The first polarizations traveling along the first and the second waveguides 35, 40 meet at the first protrusion 39 formed in the middle area of the first waveguide 35 and advance toward the first guide tube 46, and they also meet at the second protrusion 44 formed in the middle area of the second waveguide 40 and advance toward the second guide tube 47. The first polarizations traveling along the first guide tube 46 and the second guide tube 47 are nixed at the first mixing tube 45 and then are discharged through the first main opening 48.

[161] On the other hand, the second polarizations guided to the second polarization guide 50 through the polarization filtering units 20 change their advancing direction due to the first and the second direction change protrusions 56, 61 at the opposite ends of each of the third and the fourth waveguides 55, 60. Then, the second polarizations are reflected on the first and the second inclined surfaces 57, 62 formed on the surfaces facing the first and the second direction change protrusions 56, 61 and travel along the third and the fourth waveguides 55, 60. The second polarizations traveling along the third waveguide 55 meet and are nixed at the third protrusion 58 and then advance toward the second nixing tube 65, whereas the second polarizations traveling along the fourth waveguide 60 meet and are nixed at the fourth protrusion 63 and then advance toward the second nixing tube 65. The second polarizations provided from the third waveguide 55 and the fourth waveguide 60 are nixed with each other in the second nixing tube 65 by the fifth protrusion 66 and are discharged to the outside through the second main opening 68.

[162] Hereinafter, a process of transmitting the first polarizations and second polarizations through the horn array antenna for dual linear polarization will be described.

[163] The second polarizations incident on the second nixing tube 65 are separated by the fifth protrusion 66 and are guided into the third and the fourth waveguides 55, 60. The second polarizations are separated once again in the third and the fourth waveguides 55, 60 by the third and the fourth protrusions 58, 60, and the separated second polarizations are reflected on the first and the second inclined surfaces 57, 62 and provided to the first and the second direction change protrusions 56, 61. The second polarizations change their advancing direction toward the polarization filtering units 20 due to the presences of the first and the second direction change protrusions 56, 61 and travel up through the polarization filtering units 20.

[164] On the other hand, the first polarizations incident on the first nixing tube 45 are separated into the first guide tube 46 and the second guide tube 47 and are transmitted to the first and the second waveguides 35, 40, respectively. The first polarizations are separated in the first and the second waveguides 35, 40 due to the first and the second protrusions 39, 44 and travel toward the respective openings. The first polarizations emitted from the openings to the respective polarization filtering units 20 are combined with the second polarizations from the second polarization guide 50 and are radiated to the air through the inclined parts 15.

[165] Hereinafter, a layered structure for fabricating the horn array antenna 1 for dual linear polarization will be described in the unit of antenna.

[166] FIG. 25 is an exploded perspective view illustrating layers for farbricating the horn array antennal for dual linear polarization in the unit of antenna according to the exemplary embodiment of the present invention.

[167] The horn array antenna for dual linear polarization is fabricated by forming lst-5th layers 100-500 separately as shown in FIG. 25 and then depositing the layers one another. Herein, the 1st layer 100 forms the first rib 70, the 2nd layer 150 forms the second rib 75, the 3rd layer 200 forms the horns 10, the 4th-llayer 250 through the 4th-4 layer 400 form the first polarization guide 30, and the 5th- 1 layer 450 and the 5th-2 layer 500 form the second polarization guide 50.

[168] FIG. 26 is a perspective view of the 1st layer of FIG. 24, and FIG. 27 is a perspective view of the 2nd layer of FIG. 24.

[169] The 1st layer 100 and the 2nd layer 150 form the first rib 70 and the second rib 75 respectively, and the first rib 70 and the second rib 75 are formed in correspondence to the horns 10 such four (4) openings are formed for a single horn 10.

[170] FIG. 28 is a perspective view of a 1st layer and a 2nd layer according to another exemplary embodiment of the present invention, FIG. 29 is a transparent perspective view of the 1st layer and the 2nd layer of FIG. 28, and FIG. 30 is a bottom view of the 1st layer and the 2nd layer of FIG. 28.

[171] In the embodiment shown in FIGS. 26 and 27, the first rib 70 and the second rib 75 are separately fabricated using the 1st layer 100 and the 2nd layer 150. However, in this embodiment, a combining layer 160 is formed by integrally combining the 1st layer 100 and the 2nd layer 150 of FIGS. 26 and 27 such that the first rib 70 and the second rib 75 are integrally formed.

[172] In this case, as a single mould is required, a processing cost can be reduced and a time required for assembly can be also reduced.

[173] FIG. 31 is a top view of the 3rd layer of FIG. 24, and FIG. 32 is a perspective view of the 3rd layer of FIG. 24.

[174] The plurality of horns 10 is formed on the 3rd layer 200. The inclined parts 15 are formed on a plane side of the 3rd layer 200 and the inner openings are formed on a bottom side of the 3rd layer 200. The pair of protruding guides 18a, 18b is formed on each of the inclined parts 15 and the ledge 17 is formed on each of the inner openings. [175] FIG. 33 is a top view of the 4th- 1 layer of FIG. 24, FIG. 34 is a bottom view of the 4th- 1 layer of FIG. 24, and FIG. 35 is a transparent perspective view of the 4th- 1 layer of FIG. 24.

[176] The 4th- 1 layer 250 forms the upper areas of the first and the second waveguides 35, 40 of the first polarization guide 30 and the first guide tube 46 in association with the 4th-2 layer 300.

[177] The polarization filtering units 20, which are connected to the inner openings of the 3rd layer 200, penetrate through the 4th- 1 layer 250, and are located adjacent to corners of the 3rd layer 200. The bending protrusion 12 and the shielding screens 11 are formed inside each of the polarization filtering units 20.

[178] On the bottom of the 4th- 1 layer 250 are formed the upper areas of the first and the second waveguide 35, 40 of the first polarization guide 30, the upper area of the first guide tube 46 connected to the first waveguide 35, the upper area of the first nixing tube 45, and the polarization filtering units 20. Along these, the first protrusion 39 of the first waveguide 35 and the second protrusion 44 and the second protruding piece 49 of the second waveguide 40 are also formed.

[179] FIG. 36 is a top view of the 4th-2 layer of FIG. 24, FIG. 37 is a bottom view of the 4th-2 layer of fig. 24, and FIG. 38 is a perspective view of the 4th-2 layer of FIG. 24.

[180] On the plane of the 4th-2 layer 300 are formed the first through the fourth split plates 36, 37, 41, 42 of the first and the second waveguides 35, 40, the lower surface of the first guide tube 46, the first mixing tube 45, and the polarization filtering units 20, and on the bottom of the 4th-2 layer 300 are formed the first through the fourths split plates 36, 37, 41, 42 and the polarization filtering units 20.

[181] FIG. 39 is a top view of the 4th-3 layer of FIG. 24, FIG. 40 is a bottom view of the 4th-3 layer of FIG. 24, and FIG. 41 is a transparent perspective view of the 4th-3 layer of FIG. 24.

[182] The 4th-3 layer 350 forms the lower areas of the first and the second waveguides 35, 40 of the first polarization guide 30 and the second guide tube 47 in association with the 4th-4 layer 400.

[183] On the plane of the 4th-3 layer 350 are formed the first through the fourth split plates 36, 37, 41, 42, the polarization filtering units 20, and the first mixing tube 45, and on the bottom of the 4th-3 layer 350 are formed the first and the second waveguides 35, 40, the upper surface of the second guide tube 47, the first mixing tube 45, and the polarization filtering units 20.

[184] FIG. 42 is a top view of the 4th-4 layer of FIG. 24, FIG. 43 is a bottom view of the 4th-4 layer of FIG. 24, and FIG. 44 is a perspective view of the 4th-4 layer of FIG. 24.

[185] On the plane of the 4th-4 layer 400 are formed the first and the second waveguides 35, 40, the lower surface of the second guide tube 47, the first mixing tube 45, and the polarization filtering units 20. Herein, the first and the second steps 25 are formed on each of the polarization filtering units 20, and on the bottom of the 4th-4 layer 400 is formed the polarization filtering units 20 only.

[186] FIG. 45 is a top view of the 5th- 1 layer of FIG. 24, FIG. 46 is a bottom view of the 5th- 1 layer of FIG. 24, and FIG. 47 is a transparent perspective view of the 5th- 1 layer of FIG. 24.

[187] The 5th- 1 layer 450 forms the second polarization guide 50 in association with the 5th-2 layer 500. On the plane of the 5th- 1 layer 450 are formed the polarization filtering units 20, and on the bottom of the 5th- 1 layer 450 are formed the upper areas of the third and the fourth waveguides 55, 60 and the upper area of the second nixing tube 65.

[188] FIG. 48 is a transparent perspective view of the 5th-2 layer of FIG. 24.

[189] On the plane of the 5th lower layer 500 are formed the lower areas of the third and the fourth waveguides 55, 60 and the lower area of the second mixing tube 65.

[190] FIG. 49 is a front perspective view illustrating an example of the use of the horn array antenna for dual linear polarization according to an exemplary embodiment of the present invention, FIG. 50 is a side view of the antenna of FIG. 49, and FIG. 51 is a bottom view of the antenna of FIG. 49.

[191] According to the exemplary embodiment of the present invention, the horn array antenna for dual linear polarization includes 10x5 horns (10). That is, the horn array antenna for dual linear polarization includes 50 horns (10), 15 first polarization guides 30, and 15 second polarization guides 50. Herein, five of the first polarization guides 30 and five of the second polarization guides 50 are connected to two horns 10, not four horns 10. The number of antenna units and their arrangements can be changed according to how they are designed.

[192] The 15 first polarization guides 30 and the 15 second polarization guides 50 are connected to one another via sjmmetrical branch tubes or asjmmetrical branch tubes which are T-shaped, and discharge the first polarizations and the second polarizations through a first polarization discharge outlet (not shown) and a second polarization discharge outlet 440.

[193] In order to configure the antenna of this embodiment, a plurality of first polarization guides 30 and a plurality of second polarization guides 50 are connected to each other in a substantially identical configuration and thus a connecting configuration of the second polarization guide 50 is only described by way of an example.

[194] As shown in FIG. 51, in the horn array antenna 1000 for dual linear polarization according to the exemplary embodiment, second polarization guide- 1 501 through second polarization guide-5 505, second polarization guide-6 506 through second polarization guide- 10 510, and second polarization guide- 11 511 through second polarization guide- 15 515 are arranged with each line for 5 second polarization guides and the lines are arranged in parallel to one another. Herein, the second polarization guide- 11 511 and the second polarization guide- 15 515 each is connected to 2 horns 10 and accordingly has a size of a half of that of the second polarization guide- 1 501 through the second polarization guide- 10 510.

[195] Respective second mixing tubes 65 of the second polarization guide-6 506 and the second polarization guide- 11 511 are connected to each other via a fifth asjmmetrical branch tube 565, and the 5th asjmmetrical branch tube 565 and the second mixing tube 65 of the second polarization guide- 1 501 are connected to each other via a 1st asjmmetrical branch tube 561.

[196] Respective second mixing tubes 65 of the second polarization guide-7 507 and the second polarization guide- 12 512 are connected to each other via a 6th asjmmetrical branch tube 566, and respective second nixing tubes 65 of the second polarization guide-8 508 and the second polarization guide- 13 513 are connected to each other via a 7th asjmmetrical branch tube 567. Also, the 6th asjmmetrical branch tube 566 and the 7th asjmmetrical branch tube 567 are connected to each other via a third sjmmetrical branch tube 553.

[197] Respective second nixing tubes 65 of the second polarization guide-2 502 and the second polarization guide-3 503 are connected to each other via a 1st sjmmetrical branch tube 551, and ends of the 1st sjmmetrical branch tube 551 and the 3rd sjmmetrical branch tube 553 extend and are connected to each other via a 3rd asjmmetrical branch tube 563.

[198] The 3rd asjmmetrical branch tube 563 and the 1st asjmmetrical branch tube 561 are connected to each other via a 2nd asjmmetrical branch tube 562, and an end of the 2nd asjmmetrical branch tube 562 extends toward the second polarization discharge outlet 440 of the second polarization guide 50.

[199] Respective second mixing tubes 65 of the second polarization guide-9 509 and the second polarization guide- 14 514 are connected to each other via a 8th asjmmetrical branch tube 568, and respective second nixing tubes 65 of the second polarization guide- 10 510 and the second polarization guide- 15 515 are connected to each other via a 9th asjmmetrical branch tube 569. Also, the 8th asjmmetrical branch tube 568 and the 9th asjmmetrical branch tube 569 are connected to each other via a 4th sjmmetrical branch tube 554.

[200] Respective second nixing tubes 65 of the second polarization guide-4 504 and the second polarization guide-5 505 are connected to each other via a 2nd sjmmetrical branch tube 552, and ends of the 2nd sjmmetrical branch tube 552 and the 4th sjmmetrical branch tube 554 extends and are connected to each other via a fourth asjmmetrical branch tube 564.

[201] The 4th asjmmetrical branch tube 563 extends between the second polarization guide-4 504 and the second polarization guide-9 509, bends and extends between the second polarization guide-8 508 and the second polarization guide-9 509, and then bends and extends toward the 7th asjmmetrical branch tube 567.

[202] The 4th asjmmetrical branch tube 563 and the 2nd asjmmetrical branch tube 562 are connected to each other and their ends fluidly communicate with the second polarization discharge outlet 440 through which the second polarizations enter or exit.

[203] The 1st through the 4th sjmmetrical branch tubes 551-554 connecting the second polarization guides 50 in the horn array antenna for dual linear polarization have the same ratio of the second polarizations input through the ports 1 and 2, but the 1st through the 8th asjmmetrical branch tubes 561-569 has different ratios of the second polarizations input through the ports 1 and 2. For example, the 1st asjmmetrical branch tube 561 receives second polarizations from the second polarization gouide-6 506 and the second polarization guide- 11 511 through the port 1, while receiving second polarizations from the second polarization 1-501 though the port 2. That is, the ratio of the second polarizations input through the portl and the port 2 is 3:2. Accordingly, the respective asjmmetrical branch tubes use asjmmetrical branch tubes shown in FIGS. 52 through 54 in order to adjust output of the second polarizations which are input in different ratios.

[204] FIG. 52 (a) to (c) are a top view, a perspective view and a transparent perspective view of the asjmmetrical branch tube of FIG. 51, respectively.

[205] As shown in FIG. 52 (a) to (c), a port 1 tube 560a connected to the port 1 and a port 2 tube 560b connected to the port 2 are formed in a substantially " π " shape, and their inner edges are bent at 90° one time, whereas their outer edges are bent in several times. The port 1 tube 560a and the port 2 tube 560b are arranged to be sjmmetrical to each other and their ends toward the port 3 are arranged one on the other. A port 3 tube 560c connected to the port 3 has a height corresponding to the addition of the heights of the port 1 tube 560a and the port 2 tube 560b, and nixes second polarizations from the port 1 tube 560a and the port 2 tube 560b. An area of the port 3 tube 560c connected to the port 1 tube 560a and the port 2 tube 560b has a partition extending between the port 1 tube 560a and the port 2 tube 560b by a predetermined length, and the port 3 tube 560c is divided into an upper portion and a lower portion by this partition of the predetermined length.

[206] On the other hand, the port 1 tube 560a and the port 2 tube 560b are different from each other in their heights. This is to adjust output of the second polarizations input to the port 1 and the port 1 in the different ratios.

[207] FIG. 53 (a) to (c) are a top view, a perspective view, and a transparent perspective view of the asjmmetrical branch tube of FIG. 51 according to another exemplary embodiment, respectively.

[208] As shown in FIG. 53 (a) to (c), an asjmmetrical branch tube according to this embodiment is similar to the asjmmetrical branch tube shown in FIG. 52 (a) to (c) in that a port 1 tube 560a' connected to the port 1 and a port 2 tube 560b' connected to the port 2 are formed in a substantially " π " shape and a port 3 tube 560c'is formed at ends of the port 1 tube 560a'and the port 2 tube 560b'.

[209] However, in this asjmmetrical branch tube, a plurality of steps are formed in each of the port 1 tube 560a'and the port 2 tube 560b' and the number of steps of the port 1 tube 560a'differs from that of the port 2 tube 560b'. This is to adjust output of the second polarizations input through the port 1 and port 2 in the different ratio.

[210] Also, the steps of the port 1 tube 560a'are formed on a lower surface of the port 1 tube 560a' whereas the steps of the port 2 tube 560b'are formed on an upper surface of the port 2 tube 560b' The steps have heights which gradually becomes lower toward a conjunction area between the port 1 tube 560a'and the port 2 tube 560b'.

[211] FIG. 54 (a) to (c) are a top view, a perspective view, and a transparent perspective view of the asjmmetrical branch tube of FIG. 51 according to still another exemplary embodiment of the present invention, respectively.

[212] The asjmmetrical branch tube of FIG. 54 (a) to (c) is similar to the asjmmetrical branch tube of FIG. 53 (a) to 53(c).

[213] However, the asjmmetrical branch tube of FIG. 54 differs from that of FIG. 53 in that a step which has a small difference from another step in width and height is formed on the port 2 tube 560b", and this step may be formed in the port 1 tube 560a". Also, an area of the port 3 tube 560c" connected to the port 1 tube 560a" and the port 2 tube 560b" has a protrusion protruding inwardly the port 3 tube 560c" with a predetermined width. Accordingly, the port 3 tube 560c" has a reduced width at the corresponding area.

[214] Herein, it is natural that the number of steps and the shape of steps are adjustable according to the ratio of the second polarization input through the port 1 and the port 2.

[215] Of course, the sjmmetrical branch tube or the asjmmetrical branch tube described above can be used in the first polarization guide in the same way.

[216] The horn array antenna 1 for dual linear polarization described above has the ledges 17 formed in the horns 10 so that it is possible to maintain the efficiency of the antenna 1 even if the height of the horns 10 is reduced. Also, the second polarization guide 50 has a width larger than its height so that it is possible to reduce the height of the second polarization guide 50 and also to minimize the entire size of the horn array antenna 1 for dual linear polarization. Even if the size is reduced, the antenna performance of the horn array antenna can be improved.

[217] Although the first and the second polarizations were described with reference to an electric field in the above embodiments, they can be applied to a magnetic field. Also, the above-described embodiment is merely an example of fabricating the horns 10, the first polarization guide 30, and the second polarization guide 50. At least two of the first and the second ribs 70, 75, the horn 10, the first polarization guide 30, and the second polarization guide 50 may be fabricated at one time if necessary, for example, by an injection molding. Also, the numbers of layers for fabricating the horn 10, the first polarization guide 30, and the second polarization guide 50 are not limited those illustrated in FIGS. 25 through 48.

Claims

[1] A horn array antenna for dual linear polarization, characterized of comprising: a horn which guides incoming or outgoing electromagnetic waves; a rib which is connected to an upper portion of the horn and divides an opening of the horn into a plurality of openings; a first polarization guide which is connected to one end of the horn and has a plurality of passages arranged adjacent to one another for guiding first polarizations; and a second polarization guide which is connected to one end of the horn and is arranged in parallel to the first polarization guide, for guiding second polarizations having an electric field directivity perpendicular to the first polarizations.

[2] The horn array antenna for dual linear polarization of claim 1, characterized in that the rib comprises first ribs which are arranged in a vertical direction and a horizontal direction with a predetermined gap thereamong in a lattice pattern, and second ribs which have a width narrower than that of the first ribs and are formed between the first ribs and the horn.

[3] The horn array antenna for dual linear polarization of claim 2, characterized in that the first ribs and the second ribs are integrally formed with each other.

[4] A horn array antenna for dual linear polarization, characterized of comprising: a third layer where a horn for guiding incoming or outgoing electromagnetic waves is formed; a first layer and a second layer which are connected with an upper portion of the horn and form a rib which divides an opening of the horn into a plurality of openings; a plurality of fourth layers which are connected to one end of the horn and form a first polarization guide which has a plurality of passages formed adjacent to one other, for guiding first polarizations; and a plurality of fifth layers which are connected to one end of the horn and form a second polarization guide which is arranged in parallel to the first polarization guide, for guiding second polarizations having an electric field directivity perpendicular to the first polarizations.

[5] The horn array antenna for dual linear polarization of claim 4, characterized in that the first layer forms first ribs of the rib which are arranged in a vertical direction and a horizontal direction with a predetermined gap thereamong in a lattice pattern, and the second layer forms second ribs which have a width narrower than that of the first ribs and are arranged between the first ribs and the horn.

[6] The horn array antenna for dual linear polarization of claim 5, characterized in that the first layer and the second layer are integrally formed with each other.

[7] The horn array antenna for dual linear polarization of claim 4, characterized of further comprising: at least one sjmmetrical branch tube which connects the first polarization guide or the second polarization guide in the ratio of 1 : 1 ; and at least one asjmmetrical branch tube which connects the first polarization guide or the second polarization guide in the ratio of l:n.

[8] The horn array antenna for dual linear polarization of claim 7, characterized in that the asjmmetrical branch tube has a port 1 and a port 2 which face each other and a port 3 which is arranged in a perpendicular relation to the port 1 and the port 2, and that a port 1 tube connected to the port 1 and a port 2 tube connected to the port 2 are bent in a substantially " π " shape.

[9] The horn array antenna for dual linear polarization of claim 8, characterized in that the port 1 tube and the port 2 tube are formed such that their areas connected to the port 3 are layered one on the other in a vertical direction.

[10] The horn array antenna for dual linear polarization of claim 9, characterized in that the port 1 tube and the port 2 tube differ from each other in their heights.

[11] The horn array antenna for dual linear polarization of claim 9, characterized in that the port 1 tube and the port 2 tube each has a plurality of steps formed therein and gradually becoming lower in their heights toward the port 3, and the number of steps formed in the port 1 tube and the port 2 tube differ from each other.

[12] The horn array antenna for dual linear polarization of claim 9, characterized in that the port 1 tube and the port 2 tube each has a plurality of steps formed therein and gradually becoming lower in their heights toward the port 3, and heights and widths of the steps formed in the port 1 tube and the port 2 tube differ from each other.

[13] The horn array antenna for dual linear polarization of claim 8, characterized in that a port 3 tube connected to the port 3 has a narrow width at an area connected to the port 1 tube and the port 2 tube.