CN106549227A - A kind of dual-band dual-circular polarization common reflector - Google Patents

Abstract

The invention discloses a dual-frequency dual-circular polarization common-aperture antenna, which comprises a dielectric substrate (1) with a metal ground plate (2) on the lower surface, and a T-shaped junction (3) on the upper surface of the dielectric substrate (1). ) and the first metal patch (4), the second metal patch (5), the end of the trunk (31) of the T-shaped junction (3) is located on the edge of the dielectric substrate (1) as the feed port , the first arm (32) of the T-junction (3) is connected to the first metal patch (4) through the first band-pass filter (6), and the second arm (33) of the T-junction (3) is passed through the first The second bandpass filter (7) is connected with the second metal patch (5). The dual-frequency dual-circular polarization common-aperture antenna of the present invention has good isolation for similar frequencies and is easy to form an array.

Description

A Dual Frequency Dual Circular Polarization Common Aperture Antenna

technical field

The invention belongs to the technical field of wireless communication antennas, in particular to a dual-frequency dual-circular polarization common-aperture antenna with good frequency isolation.

Background technique

The downlink and uplink signals of the receiving and transmitting antennas of modern wireless communication systems work at different frequencies. In order to reduce the volume of the system and realize miniaturization, one method is to integrate the transmitting and receiving antennas in the same plane. If a common aperture antenna is used, the receiving and transmitting antennas working at different frequencies are integrated on the same aperture.

The existing dual-frequency common-aperture antenna, as described in the Chinese invention patent application "Single-layer dual-frequency circularly polarized microstrip array antenna" (application number: NO.201410649033.9, publication date: 2015.2.4), includes a single-layer microwave dielectric substrate, A dual-frequency circularly polarized radiation unit and a dual-frequency shared microstrip power division network. The dual-frequency circularly polarized radiation unit is composed of two independently working circularly polarized radiation patches connected by a microstrip. It adopts microstrip feeding, which is easy to form a high-gain dual-frequency circularly polarized antenna, avoids complex multi-layer feeding structure, and realizes dual-frequency dual-polarization transceiver common use.

However, its disadvantages are: when the cutoff frequency is close to the operating frequency, the frequency isolation is poor due to the gentle cutoff characteristic of the feed microstrip line.

Contents of the invention

The object of the present invention is to provide a dual-frequency dual-circular-polarization common-aperture antenna, which has good isolation for similar frequencies and is easy to form an array.

The technical solution that realizes the object of the present invention is:

A dual-frequency dual-circular-polarized common-aperture antenna includes a dielectric substrate with a metal ground plate on the lower surface, a T-shaped junction, a first metal patch, and a second metal patch on the upper surface of the dielectric substrate, so that The end of the backbone of the T-junction is set on the edge of the dielectric substrate as a feed port, the first arm of the T-junction is connected to the first metal patch through the first bandpass filter, and the second arm of the T-junction It is connected with the second metal patch through the second bandpass filter.

Compared with the prior art, the present invention has the remarkable advantages of:

1. Good frequency isolation: the present invention uses a band-pass filter with a steep cut-off characteristic to connect two circularly polarized radiation patches that work independently, and can achieve good isolation at similar frequencies;

2. Easy to form an array: using a miniaturized band-pass filter, the area occupied by the unit is reduced through a reasonable layout, and it is easy to form an antenna array.

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

Description of drawings

FIG. 1 is a schematic structural diagram of a dual-frequency dual-circular polarization common-aperture antenna of the present invention.

FIG. 2 is a schematic structural diagram of the bandpass filter in FIG. 1 .

FIG. 3 is a schematic diagram of the structural dimensions of FIG. 1 .

FIG. 4 is a schematic diagram of the structural dimensions of FIG. 2 .

Fig. 5 is a schematic structural diagram of a single patch circularly polarized microstrip antenna without a bandpass filter.

Fig. 6 is a schematic structural diagram of a single patch circularly polarized microstrip antenna loaded with a bandpass filter.

Figure 7 is the S11 diagram of a single patch without a bandpass filter that is simulated using HFSS.

Fig. 8 is an S11 diagram of a single patch loaded with a bandpass filter using HFSS for simulation.

FIG. 9 is a diagram of S11 obtained by simulation of the antenna of the present invention.

Fig. 10 is a diagram showing the variation of axial ratio with frequency obtained by simulation of the antenna of the present invention.

Fig. 11 is the simulated left-handed and right-handed circularly polarized E plane patterns of the antenna at a frequency of 8.2 GHz.

Fig. 12 is the simulated left-handed and right-handed circularly polarized E-plane patterns of the antenna at a frequency of 8.6 GHz.

Fig. 13 is a current distribution diagram when the antenna of the present invention works at a frequency of 8.2 GHz.

Fig. 14 is a current distribution diagram when the antenna of the present invention works at a frequency of 8.6 GHz.

FIG. 15 is a schematic diagram of an antenna array composed of a dual-frequency dual-circular polarization common-aperture antenna of the present invention.

FIG. 16 is a curve of the reflection coefficient of the 4×4 array obtained by simulation as a function of frequency.

FIG. 17 is a curve of the axial ratio of the 4×4 array as a function of frequency obtained through simulation.

Fig. 18 is an E-plane pattern of the antenna at f ₁ =8.2 GHz frequency.

Fig. 19 is an E-plane pattern of the antenna at f ₂ =8.6 GHz frequency.

In the figure, a metal ground plate 2, a dielectric substrate 1, a T-junction 3, a backbone 31, a first arm 32, a second arm 33, a first metal patch 4, a second metal patch 5, and a first bandpass filter 6. The second bandpass filter 7, the first rectangular slot 8, and the second rectangular slot 9.

detailed description

As shown in Figure 1, the dual-frequency dual-circular polarization common-aperture antenna of the present invention,

Including a dielectric substrate 1 with a metal ground plate 2 on the lower surface, a T-shaped junction 3, a first metal patch 4, and a second metal patch 5 are arranged on the upper surface of the dielectric substrate 1, and the T-shaped junction 3 The end of the trunk 31 is arranged on the edge of the dielectric substrate 1 as a feed port, the first arm 32 of the T-junction 3 is connected to the first metal patch 4 through the first bandpass filter 6, and the first arm 32 of the T-junction 3 The second arm 33 is connected to the second metal patch 5 through the second bandpass filter 7 .

As shown in Figure 1, the first metal patch 4 has a first rectangular slit 8, the second metal patch 5 has a second rectangular slit 9, the first rectangular slit 8 and the second rectangular slit 9 are not parallel.

There are rectangular slots 8 and 9 rotated at a certain angle on the two metal patches to realize circular polarization.

The first arm 32 and the second arm 33 of the T-junction 3 are all composed of microstrip lines, and the length of the microstrip line of the first arm 32 makes the signal of the operating frequency of the second metal patch 5 non-conductive to the first arm 32. The length of the microstrip line of the second arm 33 makes the signal of the working frequency of the first metal patch 4 non-conductive to the second arm 32 .

As shown in FIG. 2 , the first band-pass filter 6 and the second band-pass filter 7 are both steep cut-off band-pass filters.

Two open-circuit stubs with the same width as the feeder line are respectively extended from both ends of the feeder line, and the four open-circuit stub lines are bent together to form a ring, and there is a slit that rotates at a specific angle through the center of the ring to form a bandpass filter 67 .

Four open-circuit stubs 61 , 62 , 63 , 64 have a structure as shown in FIG. 2 . Among them, the stubs 61 and 62, and the stubs 63 and 64 form a pair of semi-circular hairpin resonators, which form a certain angle with the feeder and are relatively placed at both ends of the feeder.

FIG. 3 is a schematic diagram of the dimensions of the dual-frequency dual-circular polarization common-aperture antenna of the present invention.

The working frequency of the metal patch 4 is f ₁ , and the working frequency of the metal patch 5 is f ₂ .

There is a microstrip line of a specific length between the bandpass filter and the T-junction. Taking the microstrip line 32 on the left in FIG. 1 as an example, adjust the length of the microstrip line 32 so that when the metal patch ₅ operates at a frequency f2, it appears high resistance when viewed from the T-junction port to the metal patch 4. In an open state, the metal patch ₄ does not radiate at frequency f2. Similarly, the length of the microstrip line 33 is adjusted so that the metal patch ₅ does not radiate at the frequency f1. In this way, the two patches can work separately without affecting each other.

For the case where f ₁ and f ₂ frequencies are relatively close, only adjusting the length of the microstrip line cannot achieve good isolation between the two patches, so consider adding a filter on the basis of the duplexer. The metal patches 4 and 5 are loaded with a band-pass filter using a step impedance ring resonator, as shown in FIG. 5 . Two open-circuit stubs of the same width extend from both ends of the feeder, and there is a gap of a certain width between the open-circuit stubs extending from both ends, and the four open-circuit stubs are bent together into a circular shape to form a bandpass filter 6,7. In order to work normally at the two frequencies of the respective patches and realize frequency isolation, the sizes of the two bandpass filters 6 and 7 are different.

The impedance of the feed input port is 160 ohms, and the characteristic impedance of the microstrip transmission line is 160 ohms.

The present invention will be described in further detail below in conjunction with specific examples.

Example 1:

Take a single metal patch as an example to verify the isolation performance of the bandpass filter. Figure 5 shows a metal patch without a band-pass filter, and Figure 6 shows a metal patch with a band-pass filter loaded. Relevant dimensions and specifications are shown in Fig. 3 and Fig. 4. The working frequency of the antenna is f ₁ =8.2GHz, and the dielectric plate used is Rogers5880 plate with a dielectric constant of 2.2 and a thickness of 0.787mm. Combining Figure 4 and Figure 5, the main size parameters of the metal patch and the bandpass filter are as follows:

w0＝0.2mm, w1＝11.3mm, w11＝0.5mm, w3＝0.3mm, w4＝0.2mm, w5＝0.2mm, l1＝3.95mm, i1=1mm, r1=2.1mm, r2=1.65mm.

The antenna of this example is modeled and simulated in the electromagnetic simulation software HFSS.11. Fig. 7 is a simulation diagram of reflection coefficient without a band-pass filter, and Fig. 8 is a simulation diagram of reflection coefficient after loading a band-pass filter. It can be seen that compared with the reflection coefficient curve without a filter, the antenna has a significantly steeper cut _- off frequency response after loading a bandpass filter. -4dB at the time of the device, its isolation performance has been significantly improved.

Example 2:

The structure of the common-aperture dual-frequency dual-circular polarization unit loaded with a bandpass filter of the present invention is shown in Figure 1, and the relevant dimensions and specifications are shown in Figures 3 and 4, and the antenna operating frequency f ₁ =8.2GHz, f ₂ =8.6GHz , the dielectric plate used is a Rogers5880 plate with a dielectric constant of 2.2 and a thickness of 0.787 mm. Combining Figure 5 and Figure 6, the main size parameters of the common-aperture dual-frequency dual-circularly polarized antenna unit are as follows:

w0=0.2mm, w1=11.3mm, w2=10.7mm, w11=0.5mm, w21=0.5mm, w3=0.3mm, w4=0.2mm, w5=0.2mm, w6=0.3mm, w7=0.2mm, w8=0.2mm, l1=3.95mm, l2=4mm, i1=1mm, i2=1.1mm, d1=9mm, d2=7.2mm, r1=2.1mm, r2=1.65mm, r3=1.94mm, r4=1.5mm.

Figure 9 is the curve of reflection coefficient varying with frequency obtained by simulation, Figure 10 is the curve of axial ratio varied with frequency obtained by simulation, Figure 11 is the left-handed and right-handed circular polarization E-plane pattern of the antenna at f ₁ frequency, Figure 12 is the left-handed and right-handed circularly polarized E-plane pattern of the antenna at f ₂ frequency. When f ₁ = 8.2GHz, S11 = -22dB, axial ratio AR = 0.97dB, mainly radiating right-handed circularly polarized waves; when f ₂ = 8.6GHz, S11 = -25dB, axial ratio AR = 1.15dB, mainly radiating left-handed circular polarization circularly polarized waves. Figure ₁₃ is the current distribution diagram when the antenna works at f1 frequency, and Figure ₁₄ is the current distribution diagram when the antenna works at f2 frequency. It can be seen from the current distribution diagram that at _f1 and f2 frequencies, only the corresponding patch radiates, and the other patch does not work, and the _two patches achieve good isolation at the operating frequency.

Example 3:

In order to verify the effectiveness of the array of the present invention, the size of the array is selected as 4×4, and a coaxial probe is used to feed power from the middle. In consideration of reducing the antenna size, the antenna layout is shown in FIG. 15 . To avoid grating lobes, the element spacing is set to 30mm. The dielectric plate adopts Rogers5880 plate with a dielectric constant of 2.2, a thickness of 0.787mm, and a size of 140mm×140mm. Antenna operating frequency f ₁ =8.2GHz, f ₂ =8.6GHz. The size parameters obtained after optimization are:

w0=0.2mm, w1=11.34mm, w2=10.66mm, w11=0.5mm, w21=0.5mm, w3=0.3mm, w4=0.2mm, w5=0.2mm, w6=0.3mm, w7=0.2mm, w8=0.2mm, l1=2.9mm, l2=4mm, i1=1mm, i2=1.1mm, d1=9mm, d2=7.2mm, r1=2.1mm, r2=1.65mm, r3=1.94mm, r4=1.5mm.

Figure 16 is the simulated curve of the 4×4 array reflection coefficient changing with frequency, Figure 17 is the simulated curve of the 4×4 array axial ratio changing with frequency, and Figure 18 is the E of the antenna at f ₁ =8.2GHz frequency Plane pattern, Fig. 19 is the E-plane pattern of the antenna at f ₂ =8.6GHz frequency. When f ₁ =8.2GHz, S11=-21.6dB, axial ratio AR=0.92dB, mainly radiating right-handed circularly polarized waves, with a gain of 19.65dB; when f ₂ =8.6GHz, S11=-24.5dB, axial ratio AR= 0.11dB, the main radiation left-handed circularly polarized wave gain is 19.75dB. It can be seen that after the array is formed, the isolation between the two frequencies of the antenna is still very good, indicating that the common-aperture dual-frequency dual-circularly polarized microstrip antenna unit of the present invention is easy to form an antenna array.

In summary, a common-aperture dual-frequency dual-circularly polarized microstrip antenna unit of the present invention that is loaded with a bandpass filter to realize frequency isolation adopts two patches that work at different frequencies and polarizations, and the two patches The phase connection composition can be regarded as two parallel branches, and the two patches can be designed separately to achieve specific functions; a bandpass filter with a steep cut-off characteristic and a patch with a standing wave characteristic of a microstrip line to achieve a similar frequency isolation between chip antennas. In addition, the compact structure of the filter is convenient for forming an array, and can be well applied to a common-aperture dual-band antenna.

Claims (4)

1. A dual-frequency dual-circular polarization common-aperture antenna is characterized in that: Comprising a dielectric substrate (1) with a metal ground plate (2) on the lower surface, a T-junction (3) and a first metal patch (4), a second metal patch on the upper surface of the dielectric substrate (1) piece (5), the end of the trunk (31) of the T-shaped junction (3) is set on the edge of the dielectric substrate (1), as a feed port, the first arm (32) of the T-shaped junction (3) passes through The first bandpass filter (6) links to each other with the first metal patch (4), and the second arm (33) of the T-shaped junction (3) passes through the second bandpass filter (7) and the second metal patch ( 5) connected. 2. The co-aperture antenna according to claim 1, characterized in that: the first metal patch (4) is provided with a first rectangular slit (8), and the second metal patch (5) is provided with a first rectangular slit (8). Two rectangular slits (9), the first rectangular slit (8) and the second rectangular slit (9) are not parallel. 3. common aperture antenna according to claim 1, is characterized in that: first arm (32) and the second arm (33) of described T-junction (3) are all made of microstrip line, first arm ( The length of the microstrip line of 32) makes the signal of the operating frequency of the second metal patch (5) non-conductive for the first arm (32), and the length of the microstrip line of the second arm (33) makes the first metal patch (4 ) The signal of the working frequency is not conducted for the second arm (33). 4. The common-aperture antenna according to claim 1, characterized in that: the first band-pass filter (6) and the second band-pass filter (7) are both steep cut-off band-pass filters.