CN103972658B - The double-circle polarization microstrip antenna of wideband wide scan - Google Patents

Abstract

The present invention relates to the double-circle polarization microstrip antenna of wideband wide scan.Comprise base, two pieces in cross-shaped micro-band plate and radome; Two pieces of micro-band plates are respectively equipped with feeder line, Ba Lun and antenna oscillator, and base is that the circle of open top is box-like, and two pieces of cross-shaped micro-band plates are fixed in base, and the bottom of base offers two interface holes; The dome shape that radome is uncovered bottom being, is integrated with parasitic radiation sheet, is located on base in cover.Working band of the present invention is wide, and the relative bandwidth of standing wave≤3 is more than 40%; Be suitable for frequency range wide, centre frequency all can adopt this structure at 0.5GHz ~ 5GHz; Wide as scanning angle during phase array, the active standing wave of the comprehensive scanning in ° elevation angle, 21% bandwidth ± 60 is no more than 1.9; Volume is little, and diameter is 0.4 wavelength; Stability Analysis of Structures is reliable, has good antidetonation and dust and moisture performance.

Description

Dual circularly polarized microstrip antenna with wide bandwidth and angular scanning

technical field

The patent of the invention relates to a wide-band dual circularly polarized antenna suitable for wide-angle scanning, which belongs to the field of microwave technology and can also be used in microwave communication, modern radar systems, radio frequency identification, electronic equipment and other fields.

technical background

Antennas are important components of systems such as wireless broadcasting, wireless communication, and wireless detection. The performance of antenna units and antenna arrays directly reflects and largely affects the performance of the entire system. With the rapid development of active phased array technology, radar and other systems have higher and higher requirements for frequency bandwidth and scanning angle, which also put forward higher and higher requirements for the function and performance of the antenna.

For circularly polarized antennas, the commonly used forms include horn antennas, cross Vivaldi antennas, microstrip patch antennas, dipole antennas, etc. From a structural point of view, the horn antenna is very large in size and weight; although the cross Vivaldi antenna has a wide bandwidth, it is large in size and high in profile; the microstrip patch antenna has the advantages of light weight, small size, easy processing and integration. It has been widely used in design, but limited by its planar form, the impedance bandwidth of a single-layer microstrip patch antenna is difficult to exceed 15%, and its performance is particularly limited when used for wide-angle scanning; as for the dipole antenna form, a cross can also be used Crossed metal arm vibrator, but the metal vibrator and feeder process and structure are complex, and the weight is much heavier than the microstrip form, especially for lower frequencies.

Contents of the invention

In order to be suitable for large-scale engineering applications, while taking into account or improving electrical performance, while ensuring installation stability and structural strength, the invention provides a dual circularly polarized microstrip antenna with wide bandwidth and angular scanning.

The present invention is a crossed microstrip dipole antenna, which is composed of two crossed microstrip dipoles, an independent radome with integrated parasitic radiation unit, an integrated skirt and a base for installing lugs, forming a module with two radio frequency ports chemical unit structure. This structural form makes it have the excellent wide-bandwidth angular scanning performance of the dipole antenna in addition to the advantages of flexible form and easy processing of the conventional microstrip antenna. The relative bandwidth of its VSWR≤3 exceeds 40%, and the active standing wave VSWR≤1.9 and axial ratio AR≤3dB when the phased array scanning angle coverage of 21.2% bandwidth exceeds ±60°; the structure is compact (the unit diameter is only 0.4 λ ₀ ), the modular unit radome-microstrip plate-fixed base structure makes it very convenient to install, adjust and maintain in large-scale engineering applications.

Concrete technical solution of the present invention is as follows:

The dual circularly polarized microstrip antenna with wide bandwidth and angular scanning includes a base 4, two crossed microstrip plates and a radome 1; the two microstrip plates are A-type microstrip plate 2 and M-type microstrip plate 3 , and the height and shape of the A-type microstrip plate 2 and the M-type microstrip plate 3 are the same;

The middle part of the A-type microstrip plate 2 is provided with an A-plate long slot 23 passing through the bottom edge along the vertical direction, and one side of the A-type microstrip plate 2 is provided with an inverted hook shape around the A-plate long slot 23. A plate feeder 25; one end of the A plate feeder 25 is located in the middle of the A-type microstrip plate 2, and the other end is the A-plate feed point 22, and is located at the bottom edge of the A-type microstrip plate 2, and the long slot of the A-plate The A-board feeder 25 corresponding to the top of 23 is an upwardly protruding A-board feeder inflection point 28; the A-board feeder 25 connected to the A-board feeder 22 is connected in series with the A-board impedance matching section 24; 23 as a benchmark, on the other side of the A-type microstrip board 2, a strip-shaped A-plate copper-clad area is provided on the basis of the A-plate long slot 23; the strip-shaped A-plate copper-clad area is formed by the A-type microstrip board The copper-clad strip on the bottom edge of 2, the A-board feeding balun 27 along both sides of the A-board long slot 23 and the A-board antenna vibrator 26 of an umbrella-shaped structure are formed; between the lower part of the A-board feeding balun 27 A board short wire 21 connection;

The top of the M-type microstrip plate 3 is provided with a short slot 33 of the M-plate running through the top edge along the vertical direction, and the middle part of one side of the M-type microstrip plate 3 is provided with an inverted M-shaped M-plate feeder 35; the M-plate feeder One end of 35 is positioned at the middle part of M type microstrip plate 3, and the other end is M plate feed point 32, and is positioned at the base of M type microstrip plate 3; M plate feeder 35 corresponding to the lower end of M plate short slot 33 The place is the M-board feeder inflection point 38 which is concave downward; the M-board feeder 35 connected with the M-board feed point 32 is connected with the M-board impedance matching section 34 in series; On the other side of the plate 3, a strip-shaped M-plate copper-clad area is provided on the basis of the short slot 33 of the M-plate; The M-plate feeder balun 37 on both sides of the M-plate short slot 33 and the M-plate antenna vibrator 36 of an umbrella structure; the M-type microstrip board 3 between the lower part of the M-plate feeder balun 37 is provided with an M-plate through hole 31;

Through the cooperation of the A-plate long slot 23 on the A-type microstrip plate 2 and the M-plate short slot 33 on the M-type microstrip plate 3, the A-type microstrip plate 2 and the M-type microstrip plate 3 are crossed shape;

The base 4 is in the shape of a round box with an open top, and the cross-shaped A-type microstrip plate 2 and the M-type microstrip plate 3 are fixed in the base 4, and the bottom of the base 4 is provided with two interface holes;

Described radome 1 is the dome shape of bottom opening, and the top in it is provided with sheet metal 12; The radome 1 cover is arranged on the base 4; The distance between the strip plate 2 and the top of the M-type microstrip plate 3 is 0.1 λ ₀ -0.2 λ ₀ , where λ ₀ is the free-space intermediate frequency wavelength.

The A-type microstrip plate 2 and the M-type microstrip plate 3 are flat plates with the same size, and the upper part can be provided with a cut angle according to the inclination of the vibrator arm.

The metal sheet 12 is circular, and a small hole is opened at the center of the circle.

The bottom surface in the base 4 is distributed in a cross shape with four small metal vertical plates 43, wherein two small vertical plates are on a straight line, and the other two small vertical plates are on another straight line perpendicular to the straight line. , the A-type microstrip plate 2 is connected to two small vertical plates on a straight line through threaded connectors, and the M-type microstrip plate 3 is connected to the other two small vertical plates on an orthogonal straight line through threaded connectors. Riser.

The lower parts of both sides of the A-type microstrip plate 2 are respectively symmetrically provided with right-angled grooves, and the lower parts of the two sides of the M-type microstrip plate 3 are respectively symmetrically provided with right-angled grooves; the two sides of the A-type microstrip plate 2 The right-angled grooves make the upper part of the A-type microstrip board 2 buckle on the cylindrical wall of the base 4, and the right-angled grooves on both sides of the M-type microstrip board 3 make the upper part of the M-type microstrip board 3 buckle on the cylindrical wall of the base 4 superior.

The invention provides a dual-polarized antenna suitable for active phased array radar and having wide-bandwidth angular scanning performance, which is characterized by small size, modular design suitable for mass production and assembly, and good shock resistance and dust resistance Moisture resistance. And it adopts the form of microstrip, which has the advantages of high yield and simple process. Its technical parameters are as follows:

1. The relative bandwidth of the standing wave ≤ 3 exceeds 40%, and the structure can be used in the center frequency of 0.5GHz~5GHz;

2. Normal axis ratio ≤ 0.3dB, active standing wave ≤ 1.5;

3. Active phased array used for 21.2% bandwidth, when scanning to ±60° elevation angle, omni-directional scanning active standing wave ≤ 1.9, the axial ratio of left-handed circular polarization and right-handed circular polarization are both less than 3dB;

4. The diameter is only 0.4 wavelength, and the height is 0.42 wavelength.

Description of drawings

Figure 1 is a schematic diagram of the structure of the present invention (without radome).

Fig. 2 is the right side view of Fig. 1 .

Fig. 3 is an explosion diagram of the present invention (without radome).

FIG. 4 is a schematic diagram of a side structure of a type A microstrip plate.

Fig. 5 is a schematic diagram of another side structure of the A-type microstrip plate.

FIG. 6 is a schematic diagram of a side structure of an M-type microstrip plate.

Fig. 7 is a schematic diagram of another side structure of the M-type microstrip plate.

Fig. 8 is a sectional view of the radome.

FIG. 9 is a sectional view of the overall structure of the antenna unit.

Serial numbers in the above picture: radome 1, A-type microstrip board 2, M-type microstrip board 3, base 4, metal sheet 12, A board short wiring 21, A board feed point 22, A board long slot 23, A Board impedance matching section 24, A board feeder 25, A board antenna vibrator 26, A board feed balun 27, A board feeder inflection point 28, A board mounting hole 29, M board through hole 31, M board feed point 32, M board Board short slot 33, M board impedance matching section 34, M board feeder 35, M board antenna vibrator 36, M board feed balun 37, M board feeder inflection point 38, M board installation hole 39, small vertical board 43, A Board interface hole 44, M board interface hole 45.

detailed description

The present invention will be further described through the embodiments below in conjunction with the accompanying drawings.

Example 1

This embodiment provides an active phased array antenna design, the working frequency is 2.1GHz~2.6GHz, the polarization mode is left-handed circular polarization and right-handed circular polarization, and the array form adopts the row-column spacing of 61.5mm and 71mm The triangular grid, with a scanning pitch angle of ±60°, is required to have good shock and vibration resistance and dust and moisture resistance.

Referring to Fig. 1 and Fig. 2, the dual circularly polarized microstrip antenna of wide bandwidth angular scanning comprises base 4, two crossed microstrip plates and radome 1; Two microstrip plates are A-type microstrip plates 2 and M Type A microstrip plate 3; A-type microstrip plate 2 and M-type microstrip plate 3 are flat plates of the same size, both of which are microstrip plates with thickness t = 0.762mm and relative permittivity ε _r = 2.94, and the upper part is based on the vibrator The arm inclination is provided with chamfered corners.

Referring to Fig. 5, the middle part of the A-type microstrip board 2 is provided with an A-plate long slot 23 passing through the bottom along the vertical direction, and one side of the A-type microstrip board 2 is provided with an inverted bend around the A-plate long slot 23 Hook-shaped A-plate feeder 25; one end of the A-plate feeder 25 is located in the middle of the A-type microstrip plate 2, and the other end is the A-plate feed point 22, and is positioned at the bottom edge of the A-type microstrip plate 2, which is as long as the A-plate The A-plate feeder 25 corresponding to the top of the slot 23 is an upwardly protruding A-plate feeder inflection point 28 . A plate impedance matching section 24 is connected in series on the A plate feeder 25 adjacent to the A plate feed point 22; Referring to Fig. The long slot 23 of the A board is provided with a strip-shaped copper-clad area of the A-board; The A-plate feeding balun 27 on the side and the A-plate antenna vibrator 26 of umbrella structure; The feeding baluns 27 are short-circuited by the A-board short-circuit wire 21.

Referring to Fig. 7, the top of M type microstrip plate 3 is provided with the M plate short slot 33 that runs through the top edge along the upright direction, and the middle part of one side of M type microstrip plate 3 is provided with inverted M-shaped M plate feeder 35; M One end of plate feeder 35 is positioned at the middle part of M type microstrip plate 3, and the other end is M plate feed point 32, and is positioned at the base of M type microstrip plate 3; M plate corresponding to the lower end of M plate short slot 33 The feeder line 35 is a concave M-plate feeder inflection point 38; the M-plate feeder 35 adjacent to the M-plate feed point 32 is connected in series with the M-plate impedance matching section 34; see Fig. 6, taking the M-plate short slot 33 as a reference , on the other side of the M-type microstrip board 3, a strip-shaped M-plate copper-clad area is provided on the basis of the short slot 33 of the M-plate; Copper-clad edge strip, M-board feeder balun 37 along both sides of M-board short slot 33 and M-board antenna vibrator 36 of umbrella structure; There is a through hole 31 on the M board, and the A board short wire 21 in the middle of the lower part of the A board passes through this hole to bridge the A board feeder balun 27, and the lower part of the M board feeder balun 37 is on the M type microstrip board 3 The two ends of each are provided with M-board installation holes 39 respectively.

The total length of the antenna dipole arm is generally half or slightly shorter than the wavelength corresponding to the center frequency, and the height of the dipole arm from the reflecting surface is about a quarter of the wavelength.

The feeders of the two oscillators are respectively designed with an impedance matching section 24 of the A board and an impedance matching section 34 of the M board. In order not to affect the power capacity of the antenna, high-impedance narrow lines should be avoided for impedance transformation. For ports and feeders with a characteristic impedance of 50Ω, a transformation section with a characteristic impedance of 60Ω~100Ω can be selected for impedance matching. At the same time, for this type of structural dipole antenna, in order not to affect the feeder structure, the length of the matching section generally does not exceed 0.2 times the wavelength of the transmission line. By adjusting the position, length, and width of the impedance transformation section, the impedances of the two oscillators can be matched separately, so as to reduce the reflection caused by mismatch and achieve higher efficiency. In addition to the impedance matching section, by adjusting the positions of the inflection point 28 of the A-board feeder line and the position of the M-board feeder inflection point 38, the lengths of the two feeder lines can be adjusted respectively, thereby adjusting the phase difference of the two vibrators to achieve more accurate matching. Polarized antennas also allow for better axial ratios.

Referring to Fig. 3, by the cooperation of the A board long slot 23 on the A type microstrip board 2 and the M board short slot 33 on the M type microstrip board 3, the A type microstrip board 2 and the M type microstrip board 3 is in the shape of a cross; the long slot 23 of the A board and the short slot 33 of the M board are connected near the center of the antenna vibrator 26 of the A board and the antenna vibrator 36 of the M board. The feeders of the two vibrators bypass the long slot 23 of the A board and the short slot 33 of the M board from the upper end and the lower end respectively and fold to the other half to achieve balanced excitation of the antenna dipole. In order to suppress unnecessary radiation, the feeder can be turned Sharp corners are cut off. Each antenna unit has two excitation ports, that is, the feed point 22 of the A board and the feed point 32 of the M board, and the polarization mode of the antenna can be changed by changing the excitation amplitude and relative phase relationship of the two ports. The excitation with equal amplitude and phase difference of 90° or -90° can realize left-handed circular polarization or right-handed circular polarization. If the two ports are excited separately, two kinds of linear polarizations orthogonal to each other can be provided respectively.

Referring to Figure 3, the base 4 is in the shape of a round box with an open top, and the outer diameter and inner diameter are Db = _50mm and _Dr = 53mm respectively. By adjusting the height of the cylindrical wall of the base 4, the mutual coupling effect between units can be significantly improved and Active standing waves during wide-angle scanning. The design of the cylindrical wall not only weakens the mutual coupling between the units but also widens the lobe width of the unit, which greatly improves the wide-angle scanning performance and bandwidth of the antenna. The bottom of the base 4 is respectively provided with an A-board interface hole 44 and an M-board interface hole 45. The medium of the connector should not be lower than the bottom surface of the inner cavity of the base 4 so that it can be inserted into the A-board interface hole 44 and the M-board interface on the base 4. The raised medium behind the hole 45 just touches the A-board feeding point 22 and the M-board feeding point 32 of the microstrip board, and the base 4 can provide a reliable connection ground for the connector. The connector can be fixed to the base 4 with screws. For the circularly polarized antenna, it is necessary to connect a 3dB bridge with a phase output difference of 90°, which can be installed directly under the base 4 .

The bottom surface in the base 4 is cross-shaped and fixedly installed with four small metal vertical plates 43, wherein two small vertical plates are on a straight line, and the other two small vertical plates are on another straight line; each small vertical plate The height h _f =6mm, in order not to affect the electrical performance of the antenna, the ground part of the feed balun should be higher than the height h _f of the small vertical plate. The A-type microstrip board 2 is connected to two small vertical boards on a straight line through threaded connectors, and the M-type microstrip board 3 is connected to the other two small vertical boards on a straight line through threaded connectors. Referring to Fig. 9, right-angle grooves are arranged symmetrically on both sides of the A-type microstrip board 2, and right-angle grooves are symmetrically arranged on the lower parts of the two sides of the M-type microstrip board 3; the upper part of the A-type microstrip board 2 The upper part of the M-type microstrip board 3 is buckled on the cylindrical wall of the base 4 through the right-angle grooves on both sides. The height of the vibrator microstrip plate is H _m =43mm, and the total height of the antenna unit is H _r =55mm.

Referring to Fig. 8, the radome 1 is in the shape of a dome with an open bottom, and a circular metal sheet 12 is installed on the top inside, and a small hole is opened in the center of the metal sheet 12; the radome 1 is covered by a buckle. On the base 4; the distance dp ₌ 20mm between the metal sheet 12 in the radome 1 and the cross-shaped A-type microstrip plate 2 and the M-type microstrip plate 3 top; the metal sheet 12 is used as the parasitic unit of the antenna vibrator, By adjusting its radius and height (that is, the height of the radome), the frequency band and scanning performance of the antenna can be significantly improved.

The diameter of the antenna unit (including the radome) is only 0.40 λ ₀ , the height is 0.42 λ ₀ , and the relative bandwidth exceeds 40%. There is still room for further optimization according to application requirements. In order to reduce the number of radiation units, the array form adopts a triangular grid, and the scanning angle reaches ±60° in the 2.1GHz~2.6GHz frequency band, and the active standing wave VSWR at each scanning angle of the left-handed and right-handed circular polarization in the frequency band is different. Greater than 1.9, the axis ratio of the maximum scan angle is less than 3dB. The antenna has the advantages of small size, excellent electrical performance, dust-proof and moisture-proof, and is convenient for engineering installation and maintenance. It can also be applied to other frequency bands and other polarization situations with a slight adjustment.

Claims (5)

1. the double-circle polarization microstrip antenna of wideband wide scan, is characterized in that: comprise base (4), micro-band plate of two pieces of right-angled intersections and radome (1); Described two pieces of micro-band plates are the micro-band plate of A type (2) and the micro-band plate of M type (3), and the micro-band plate of A type (2) is identical with shape with the height of the micro-band plate of M type (3);

The middle part of the micro-band plate of described A type (2) offers A plate elongated slot seam (23) on through base along vertical direction, a side pressed on ring of the micro-band plate of A type (2) is provided with down the A plate feeder line (25) of hook solid around A plate elongated slot seam (23); One end of A plate feeder line (25) is positioned at the middle part of the micro-band plate of A type (2), the other end is A plate feedback point (22), and being positioned at the base place of the micro-band plate of A type (2), A plate feeder line (25) place of stitching the top of (23) corresponding with A plate elongated slot is A plate feeder line flex point (28) raised up; The anti-matching section of A plate resistance (24) that A plate feeder line (25) that point (22) is connected connects is presented with A plate; With A plate elongated slot seam (23) for benchmark, the another side of the micro-band plate of A type (2) covers copper region with A plate elongated slot seam (23) for benchmark is provided with banded A plate; Banded A plate covers copper region and is covered copper strips by the base of the micro-band plate of A type (2), formed along A plate elongated slot seam A plate feed Ba Lun (27) of (23) both sides and the A plate antenna oscillator (26) of beveled structure; Connected by A plate shorting stub (21) between the bottom of A plate feed Ba Lun (27);

The top of the micro-band plate of described M type (3) offers the short line of rabbet joint of M plate (33) of through top margin along vertical direction, the side Middle face of the micro-band plate of M type (3) is provided with the M plate feeder line (35) of the shape of falling M; One end of M plate feeder line (35) is positioned at the middle part of the micro-band plate of M type (3), and the other end is M plate feedback point (32), and is positioned at the base place of the micro-band plate of M type (3); M plate feeder line (35) place corresponding with the lower end of the short line of rabbet joint of M plate (33) is to recessed M plate feeder line flex point (38); The anti-matching section of M plate resistance (34) that M plate feeder line (35) that point (32) is connected connects is presented with M plate; With the short line of rabbet joint of M plate (33) for benchmark, the another side of the micro-band plate of M type (3) covers copper region with the short line of rabbet joint of M plate (33) for benchmark is provided with banded M plate; Banded M plate covers copper region and is covered copper strips by the base of the micro-band plate of M type (3), formed along M plate feed Ba Lun (37) of the short line of rabbet joint of M plate (33) both sides and the M plate antenna oscillator (36) of beveled structure; The micro-band plate of M type (3) between M plate feed Ba Lun (37) bottom offers M plate through hole (31);

Stitched the cooperation of the short line of rabbet joint of M plate (33) on (23) and the micro-band plate of M type (3) by the A plate elongated slot on the micro-band plate of A type (2), make the micro-band plate of A type (2) and the micro-band plate of M type (3) in cross-shaped;

The circle that described base (4) is open top is box-like, and the cross-shaped micro-band plate of A type (2) and the micro-band plate of M type (3) are fixed in base (4), and the bottom of base (4) offers two interface holes;

Described radome (1) is the uncovered dome shape in bottom, and the top in it is provided with sheet metal (12); Radome (1) is located on base (4); Sheet metal (12) in radome (1) is 0.1 apart from the distance between the cross-shaped micro-band plate of A type (2) and the micro-band plate of M type (3) top λ ₀ ~ 0.2 λ ₀ , described in λ ₀ for free space intermediate frequency wavelength.

2. the double-circle polarization microstrip antenna of wideband wide scan according to claim 1, is characterized in that: the flat board that the micro-band plate of described A type (2) is identical with sized by the micro-band plate of M type (3), and top can arrange corner cut according to oscillator arms gradient.

3. the double-circle polarization microstrip antenna of wideband wide scan according to claim 1 and 2, is characterized in that: described sheet metal (12) is for circular, and circle centre position offers aperture.

4. the double-circle polarization microstrip antenna of wideband wide scan according to claim 1 and 2, it is characterized in that: the small vertical plate (43) bottom surface in base (4) being distributed with four blocks of metals in crosswise, wherein two pieces of small vertical plates point-blank, another two pieces of small vertical plates are on the another straight line mutually orthogonal with described straight line, the micro-band plate of described A type (2) is threaded connection part and is connected to two pieces of small vertical plates point-blank, and the micro-band plate of described M type (3) is threaded connection part and is connected to the another two pieces of small vertical plates in orthogonal straight lines.

5. the double-circle polarization microstrip antenna of wideband wide scan according to claim 1 and 2, it is characterized in that: the dual-side bottom of the micro-band plate of described A type (2) is arranged with right angle groove respectively, the dual-side bottom of the micro-band plate of described M type (3) is arranged with right angle groove respectively; The right angle groove of the micro-band plate of A type (2) both sides makes the upper buckle of the micro-band plate of A type (2) on the cylindrical wall of base (4), and the right angle groove of the micro-band plate of M type (3) both sides makes the upper buckle of the micro-band plate of M type (3) on the cylindrical wall of base (4).