KR100929597B1 - Radiation element for dual polarization using ridge waveguide - Google Patents

Abstract

The present invention relates to a radiation element applied to an active phased array antenna that generates a double polarized wave using a ridged waveguide.

The present invention can further reduce the cutoff frequency of the rectangular waveguide by using the ridged waveguide, and expand the frequency bandwidth by providing a shorting pin. In addition, since a thin substrate is inserted into the empty space inside the waveguide, no additional space is required, and two independent radiating elements can be simultaneously implemented in a limited space, thereby effectively using the space. In addition, polarization orthogonal to each other is generated for the two input terminals, and the arrangement period can be reduced while increasing the range of the beam scanning angle in a limited space.

Description

The dual polarization structure of the radiating element using the open ended ridge waveguide}

The present invention relates to a radiation element applied to an active phased array antenna that generates a double polarized wave using a ridged waveguide.

One of the major components of an active phased array antenna system is a radiating element. There are various types of radiation elements, such as microstrips, waveguides, and dipoles. However, in the case of making radiation elements using open waveguides, there is generally one input terminal and one polarization. With this type of structure, it is very difficult to implement a radiation element to have a double polarization function and to reduce the arrangement period as much as possible.

In general, a radiating element is used in an array antenna system, and an RF transceiver module is attached to the rear end of an input terminal to transmit and receive a signal, and to adjust a built-in phase shifter to move a beam of the array antenna. This active array antenna moves a beam by the phase difference of a signal input to each radiation element, which is called a beam scan. The angular range of beam scanning is very closely related to the arrangement period of the radiation element. Since the grating lobe is generated when the array period is considerably larger than the wavelength, the array period should be designed so that the grating lobe does not occur while satisfying the required beam scanning angle range to be designed. When the arrangement period is determined, the radiation element should be designed so that the radiation element is installed in the space. In general, there is a technical difficulty in designing the radiation element due to the narrow space.

An object of the present invention is to propose a radiation element structure using a ridged waveguide that can lower the cutoff frequency compared to the internal size of the waveguide.

The present invention is a structure of a radiation element having dual polarization orthogonal to each of two input terminals using an open ended ridge waveguide.

In the radiation element for an active phased array antenna of the present invention, a ridge is positioned in the middle of a width of a vertical conductor inside a rectangular waveguide, and a ridge that radiates a signal input to one of two input porters at an open outlet of the waveguide. wave-guide; And a substrate inserted into the ridged waveguide and having a top and bottom dipole antenna configured to radiate a signal input to the other one of the two input ports by the dipole.

According to the present invention, the cutoff frequency of the rectangular waveguide can be further reduced by using the ridged waveguide as a radiation element, and thus, the cross-sectional size of the waveguide can be reduced. In addition, since a thin substrate is inserted into the empty space inside the waveguide, additional space is not required and two independent radiating elements can be simultaneously implemented in a limited space, thereby effectively using the space.

In addition, by the radiation element of the present invention, polarizations orthogonal to each other are generated with respect to two input terminals, and the arrangement period can be reduced while increasing the range of the beam scanning angle in a limited space. In addition, the structure of the radiation element is also very simple and can be mass produced easily.

The present invention relates to a radiation element of a type in which a printed circuit board having a dipole antenna is inserted into an open ridge waveguide. The radiation device of the present invention has two input ports and generates vertically and horizontally double polarized waves that are orthogonal to each other. In the present invention, it is possible to make the waveguide cross-sectional size smaller by using the ridged waveguide, and to design an elaborate radiation device having a structure in which a thin substrate is inserted into the waveguide.

Hereinafter, with reference to the accompanying drawings will be described in detail the structure of the radiation element according to the present invention.

1 is a diagram illustrating an active array antenna to which the radiation device of the present invention is applied.

Referring to FIG. 1, the active array antenna 100 of the present invention includes a plurality of radiation elements 105 arranged according to two input ports V and H and an array period dx and dy. The signals input to the input porter V and the input porter H, respectively, generate vertical polarization V and horizontal polarization H by the radiation elements.

To design an array antenna having dual polarization in an active array antenna, a large beam scanning angle, and a relatively wide frequency bandwidth, the size of the inside of the waveguide used in the radiating element is reduced. In general, the relationship between the internal size of the waveguide and the cutoff frequency is characterized by the fact that the larger the internal size of the waveguide, the lower the cutoff frequency. In order to increase the angle of beam scanning without the grating lobe, it is most preferable to set the array period to about half wavelength. However, if the waveguide is designed with such a small size, the cutoff frequency is high, and the electromagnetic waves cannot progress smoothly in the waveguide at the desired operating frequency. . In addition, in the case of using the existing ridge waveguide, the width of the waveguide, which is the inner size of the waveguide, is very close to the cutoff frequency, but the waveguide height is relatively low, so the waveguide height may be very small. However, such a low open ridge waveguide structure has a problem that it is difficult to radiate when radio waves are radiated into free space. In addition, there is a technical problem that two input terminals having respective polarizations are attached to one open waveguide, and at the same time, the orthogonal radio waves must radiate efficiently.

2 is a view showing an example of a radiation device structure according to the present invention.

Referring to FIG. 2, the radiation device 200 has a shape in which a substrate 250 having a dipole antenna is printed is inserted into an open ridge waveguide 210. The board 250 may be inserted into an intermediate point of the ridged waveguide 210, and two input ports V and input ports H, to which signals are input and output, may be connected to a SubMiniature A (SMA) connector. It doesn't work. The length of the waveguide 210 is shorter than the length of the substrate 250.

In FIG. 2, the signal entering the input port V is excited by electromagnetic waves by a short circuit in the upper and lower surfaces of the waveguide 210 via a very short microstrip line, and is opened after passing through the waveguide 210. Radiates from the part into free space. At this time, the radio wave is a vertical polarization (V) shown in FIG.

In addition, the signal entering the input porter H is passed through a parallel plate line through a long microstrip line and finally radiated into free space by a dipole located at the end of the substrate. At this time, the radio wave becomes the horizontal polarization (H) shown in FIG.

On the contrary, when the radio wave is received, the radio wave is transmitted in a direction opposite to the signal transmission direction described above, and then output from the input porter V and the input porter H, respectively.

As described above, since the radiation elements of the present invention coexist with radiation elements having different polarizations, they are mutually coupled but are very weak, and thus each radiation element operates almost independently.

FIG. 3A is a stereoscopic view and a detailed design diagram illustrating an example of a ridge waveguide constituting the radiation device of FIG. 2.

Referring to FIG. 3A, the ridge waveguide 210 includes an input porter V 212, an input porter H 213, a dipole 214, a shorting pin 215, and a ridge 216. The open ridge waveguide of the present invention is used to generate vertical polarization.

3B to 3E are detailed design views of the ridged waveguide of FIG. 3A, FIG. 3B is a cross-sectional view taken along aa ′ of FIG. 3A, FIG. 3C is a front view, and FIG. 3D is a cross-sectional view including a dipole and a shorting pin, and FIG. 3E. Is a side view of the input porter.

3B to 3E, the cross-sectional size inside the waveguide is represented by the width and height. The waveguide width (WGX) is determined in consideration of the arrangement period and the conductor thickness of the waveguide. The waveguide height (WGY) is determined to be smaller than the width and to be smaller than the inside of the waveguide.

The ridge 216 located in the middle of the width of the upper and lower conductor surfaces inside the waveguide is represented by the width and height. Since the width (GGX) and height (GGY) of the ridge are smaller as the gap between the top / bottom ridge and the ridge width (GGX) is wider, the cutoff frequency of the waveguide is lowered. Therefore, the operating frequency range to be designed is considered. Must be decided.

In the waveguide there is a dipole 214 that excites electromagnetic waves on the input port side and a shorting pin 215 is formed near the opposite open exit. The dipoles 214 and the shorting pins 215 arranged side by side at a predetermined interval are positioned apart from the ridge 216. In the absence of a shorting pin, the resonance occurs once due to the waveguide length WZZ and the frequency bandwidth is relatively narrow. Therefore, if the operating frequency range is large, that is, in order to increase the frequency bandwidth, a short resonance pin may be additionally provided in addition to the dipole to satisfy the required frequency range. Such a phenomenon can be confirmed by referring to FIG. 5, which is a result of calculating the return loss from the input porter V. FIG.

The input porter V 212 and the input porter H 213 are connected by an SMA connector, and are positioned according to the antenna structure of the substrate, and the dipoles 214 on an extension line in the longitudinal direction of the waveguide in the input porter V 212. ) And the shorting pin 215 are in turn.

4A is a three-dimensional view illustrating an example of a substrate configuring the radiation device of FIG. 2.

Referring to FIG. 4A, the substrate 250 includes a short microstrip line 251 connected to the input porter V 212, a long microstrip line 252 connected to the input porter H 213, and a parallel plate line 253. And a dipole antenna having a dipole 254 is designed.

4B and 4C are schematic views of the front and rear surfaces of the substrate, respectively.

4B and 4C, the length of the microstrip line 251 corresponds to the position from the input porter V 212 to the dipole 214 of the waveguide 210, and the microstrip line 252 is the waveguide 210. Coupling with the parallel plate line 253 having a length extending than the length (WZZ) of). Since the microstrip line 252 is converted into the parallel plate line 253, different characteristic impedances are connected to each other, the microstrip 252 is formed in a single step structure having a single width so that impedance matching is well performed. Is inclined by a multi-stage structure that narrows to change slowly.

5 to 8 illustrate the performance of the radiation device of the present invention in a predetermined operating frequency range.

5 is a result of calculating the return loss for the input porter V. There are two resonances within the operating frequency range (in this embodiment, about 8.3 to 10.3 GHz), and the return loss is low to satisfy the required frequency range. It can be seen that. The resonant frequency can vary depending on the length of the waveguide, the location of the shorting pin, and the position of the dipole to excite the wave within the waveguide.

FIG. 6 shows a result of calculating the return loss of the input porter H. Similarly to the characteristics of a general dipole antenna, there is a single resonance, and the reflection loss is low at about 8.3 GHz or more to sufficiently satisfy the required frequency range. have.

7 is a radiation pattern radiated into the free space from the open waveguide by entering the input porter (V), and FIG. 8 is a radiation pattern radiated by a dipole printed on a flat substrate with the input porter (H), similar to a general dipole antenna. It is showing its characteristics. It can be seen from FIG. 7 and FIG. 8 that the radiation element of the present invention exhibits a radiation pattern without deterioration of each polarization characteristic.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1 is a diagram illustrating an active array antenna to which the radiation device of the present invention is applied.

2 is a view showing an example of a radiation device structure according to the present invention.

3A to 3E are three-dimensional and detailed design diagrams illustrating an example of a ridge waveguide constituting the radiation device of FIG. 2.

4A to 4C are three-dimensional views showing an example of a substrate constituting the radiation device of FIG.

5 to 8 show the calculation result performance for the radiation element of the present invention within the operating frequency range.

Claims (4)

A ridged waveguide positioned in the middle of a width of the upper and lower conductor surfaces inside the rectangular waveguide, and radiating a signal input to one of two input porters at an open outlet of the waveguide; And And a substrate inserted into the ridged waveguide and having one dipole antenna formed thereon to radiate a signal input to the other one of the two input ports by a dipole. 2. The method of claim 1, The ridged waveguide includes a shorting pin positioned vertically to the upper and lower conductor surfaces inside the waveguide in order to extend an operating frequency range. The method of claim 1, The substrate has a microstrip line and a parallel plate line, the microstrip line has a single step structure, the ground plane is converted to the parallel plate line in the microstrip line is formed for the active phased array antenna Radiation elements. The method of claim 1, The vertical polarization is generated by the electromagnetic wave radiated from the ridge waveguide, and the horizontal polarization is generated by the electromagnetic wave radiated from the substrate.

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