Etching microstrip line type broadband wide-beam patch array antenna based on side feeding

Abstract

The invention discloses an etched microstrip line type broadband wide-beam patch array antenna based on side feeding. The antenna comprises an antenna array layer, an integrated waveguide layer and a grounding layer which are arranged in sequence. The antenna array layer is formed by linearly arranging a plurality of antenna units, each linear unit comprises a feeder line, one end of each feeder line is connected with a rectangular transmission line, and one side of each rectangular transmission line is connected with a plurality of radiation units; and the rectangular transmission line is provided with a first rectangular groove, a second rectangular groove and a third rectangular groove to form an H-shaped feed network for feeding the side edges of the plurality of radiation units. The array antenna works in a frequency band range of 75GHz-85GHz, the beam width of the E surface ranges from-22 degrees to 24 degrees, the beam width of the H surface ranges from-40 degrees to 40 degrees, and the beam width of the H surface ranges from-18 degrees to 24 degrees at 78GHz, so that broadband of a millimeter wave frequency band and wide beams of the E surface and the H surface are realized.

Description

Technical Field

[0001] The invention relates to the technical field of microwave devices, and in particular to an etched microstrip line-type wide bandwidth beam patch array antenna based on side feeding. Background Art

[0002] With the rapid development of wireless communication technology, the demand for high-performance array antennas is growing. Ultra-wideband, low-profile, and wide-beam antennas have gradually become a research hotspot. With the continuous advancement of technology, the research and application of wide-bandwidth beam antennas are constantly expanding. Satellite systems require antennas to have relatively wide beam coverage to avoid multipath and tropospheric effects commonly seen on radars; base station systems require antennas to have good directional beams; imaging systems require antennas to have wide-bandwidth beams to improve resolution; with the continuous expansion of application scenarios, research on broadband microstrip array antennas that meet wide beam requirements on both the E and H planes has important theoretical significance and potential market value.

[0003] For traditional microstrip antennas, there are several feeding methods: electromagnetic coupling feeding, where the feeding line and the patch are not in direct contact to reduce feeding loss, and slotting can be used to improve high-frequency impedance matching to effectively increase bandwidth, but the thickness of the antenna will increase, which is not conducive to miniaturization; coaxial line feeding, the outer conductor of the coaxial line can achieve electromagnetic shielding to avoid the influence of feeding on radiation, but the design is complex, the physical size is limited, and it is difficult to integrate; microstrip line feeding can be processed and designed together with the patch to achieve integration, but the feeding interferes with the radiation field of the microstrip patch, making it difficult to achieve high performance Common array feeding networks include series and parallel types. In series feeding networks, the current amplitude and phase on different elements are adjusted by adjusting the size of the feed line and the array element spacing. It generally works under traveling waves, has high space utilization, occupies little space, and has high radiation efficiency. However, phase deviations will gradually accumulate between elements, limiting bandwidth and making performance difficult to optimize. Parallel feeding networks mostly use cascaded power dividers to provide excitation to the elements. The amplitude and phase are well controlled, the beam pointing is independent of frequency, and the directional patterns are matched within the frequency band. However, the network has too many levels, resulting in large transmission losses and low space utilization. Summary of the invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes an etched microstrip linear wide bandwidth beam patch array antenna based on side feeding, which can simultaneously achieve broadband and wide beams on the E plane and the H plane.

[0005] The etched microstrip linear wide bandwidth beam patch array antenna based on side feeding proposed by the present invention comprises an antenna array layer, an integrated waveguide layer and a ground layer arranged in sequence; The antenna array layer is composed of a plurality of antenna units arranged linearly, wherein the linear unit includes a feed line, one end of the feed line is connected to a rectangular transmission line, and one side of the rectangular transmission line is connected to a plurality of radiation units; the rectangular transmission line is provided with a first rectangular groove, a second rectangular groove and a third rectangular groove, forming an H-type feeding network for feeding the sides of the plurality of radiation units.

[0006] Preferably, the size of the rectangular transmission line is (2.2λ-2.4λ)*0.125λ; the size of the first rectangular groove is (0.3λ-0.4λ)*0.075λ; the size of the second rectangular groove is (0.16λ-0.18λ)*0.075λ; the size of the third rectangular groove is (0.2λ-0.4λ)*0.075λ; wherein λ is the wavelength of the electromagnetic wave of the array antenna.

[0007] Preferably, the radiation unit comprises a rectangular patch antenna, and the rectangular patch antenna is connected to the rectangular transmission line via an L-shaped connecting line.

[0008] Preferably, the rectangular patch antenna is also symmetrically provided with two fourth rectangular grooves, which are distributed on both sides of the connection between the L-shaped connecting line and the rectangular patch antenna; the size of the rectangular patch antenna is (0.25λ-0.29)λ*0.275λ, and the size of the fourth rectangular groove is (0.055λ-0.15λ)*(0.0375λ-0.0575λ); wherein λ is the wavelength of the electromagnetic wave of the array antenna.

[0009] Preferably, a transition microstrip is further provided between the L-shaped connecting line and the rectangular transmission line; the size of the transition microstrip is (0.13λ-0.24λ)*(0.03λ-0.075λ); wherein λ is the wavelength of the electromagnetic wave of the array antenna.

[0010] Preferably, the feed line is formed of GCPW on the antenna array layer and is distributed in a U-shaped routing.

[0011] Preferably, a plurality of top-level through holes are provided on both sides of the feed line, the integrated waveguide layer is provided with waveguide through holes matching the top-level through holes, and the grounding layer is provided with grounding through holes matching the waveguide through holes, so as to realize the corresponding top-level through holes, waveguide through holes and grounding through holes being interconnected.

[0012] Preferably, the radius of the waveguide through hole is (0.03λ-0.06λ), the lateral spacing is (0.064λ-0.255λ), the longitudinal spacing is (0.08λ-0.125λ), and the height is 0.04λ-0.05λ; the spacing between the top through hole and the feed line is 0.12λ-0.14λ; wherein λ is the wavelength of the electromagnetic wave of the array antenna.

[0013] Preferably, the spacing between the antenna units is 0.6λ-0.7λ, and the antenna units are symmetrically distributed as a whole; wherein λ is the wavelength of the electromagnetic wave of the array antenna.

[0014] Beneficial technical effects of the present invention: 1. The array antenna of the present invention feeds multiple radiating units by adopting a novel serial side feeding structure. The signal is fed in series to the rectangular transmission line through the feeder line. The rectangular transmission line and each radiating unit realize the serial side feeding structure through the L-shaped connecting line. Compared with the traditional series-parallel feeding network, the serial side feeding structure proposed in this design can be similar to the parallel feeding network. The rectangular transmission line provides more uniform radiation coverage for the patch side feeding. At the same time, the structure is similar to the series feeding network, which can allow multiple radiating patches to have a wider beam width at different frequencies, and realize broadband and wide beams on the E plane and H plane at the same time; compared with the serially fed ultra-wideband microstrip array antenna developed by a domestic team for material detection, the operating frequency band of the array antenna of the present invention is 75GH z-85GHz, the bandwidth is 190% wider; compared with the K-band vehicle detection hybrid fed microstrip array antenna developed by a team of Xidian University, the beam width of the E-plane of the antenna of the present invention is from -22° to 24° at 76GHz, 78GHz, and 80GHz, and the beam width of the H-plane is from -40° to 40° at 76GHz and 81GHz, and from -18° to 24° at 78GHz. The beam widths of both the E-plane and the H-plane are greater than 2.5 times; broadband and wide beams of the E-plane and the H-plane are achieved at the same time.

[0015] 2. The array antenna of the present invention designs an H-type feeding network to distribute the excitation to the array elements. Compared with the traditional power-division parallel feeding network, the structure is simpler, and the structure can be changed to change the proportion of the distributed excitation; three rectangular grooves are etched on the rectangular transmission line. Compared with the traditional power-division parallel feeding network, the signal is distributed to the radiation unit through the H-type feeding network after being fed into the rectangular transmission line in series. This transmission structure can also achieve the current ratio distributed to the radiation unit, and the size of the three rectangular grooves can be changed to change the distribution of the current in the rectangular microstrip line, forming a uniform beam width at different frequency points. In addition, compared with the power-division parallel feeding network, the structure is simpler and the space utilization rate is high.

[0016] 3. The array antenna of the present invention adopts a microstrip line side feeding method to feed the patch antenna. The rectangular transmission line and each radiating unit realize a serial side feeding structure through an L-shaped connecting line to overcome the problem of narrow impedance bandwidth and limited performance of microstrip line feeding. The L-shaped connecting line increases the path length of the current flowing through the patch antenna. Side feeding is conducive to flexible impedance matching and generates more resonance points. It can be seen that resonance points appear in the return loss at 77.5GHz, 79GHz, and 82.2GHz, achieving broadband; compared with the average relative bandwidth of 5% of the microstrip antenna fed by the traditional microstrip line, the relative bandwidth of the array antenna of the present invention is 2.5 times the average relative bandwidth, and the return loss is less than 10dB at 75GHz-85GHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of the etched microstrip linear wide bandwidth beam patch array antenna based on side feeding proposed by the present invention; Figure 2 An exploded schematic diagram of the etched microstrip linear wide bandwidth beam patch array antenna based on side feeding proposed by the present invention; Figure 3 A top view of the array antenna layer proposed by the present invention; Figure 4 A partial enlarged view of a single antenna unit structure proposed by the present invention; Figure 5 A schematic diagram of the structure of a radiation unit in a single antenna unit proposed by the present invention; Figure 6 A schematic diagram of the structure of the integrated waveguide layer proposed in the present invention; Figure 7 The return loss parameter of the array antenna input port proposed by the present invention is Result graph; Figure 8 This is a result diagram of the beam width of the E-plane of the array antenna proposed in the present invention; Fig. 9 This is a result diagram of the beam width of the H-plane of the array antenna proposed in the present invention; Fig.10 This is a diagram of the imaging results of using other wide beam antennas and the array antenna of the present invention in the microwave imaging system proposed by the present invention.

[0018] In the figure: 1-antenna array layer, 11-feeding line, 12-rectangular transmission line, 121-first rectangular groove, 122-second rectangular groove, 123-third rectangular groove, 13-first radiation unit, 131-first transition microstrip, 132-L-type connecting line, 133-fourth rectangular groove, 14-second radiation unit, 141-second transition microstrip, 15-third radiation unit, 16-fourth radiation unit, 17-top through hole, 2-integrated waveguide layer, 21-, waveguide through hole, 3-ground layer, 31-ground through hole. DETAILED DESCRIPTION

[0019] The present invention will be further explained below in conjunction with specific embodiments.

[0020] Reference Figure 1-4 The etched microstrip linear wide bandwidth beam patch array antenna based on side feeding proposed in the present invention comprises an antenna array layer 1, an integrated waveguide layer 2 and a ground layer 3 which are arranged in sequence; the material of the integrated waveguide layer 2 is Rogers 3003, the thickness is 0.0325λ, and the dielectric constant is 3.07; the material of the antenna array layer 1 and the ground layer 3 is copper; the lengths of the antenna array layer 1, the integrated waveguide layer 2 and the ground layer 3 are 15.525λ, 17.5λ and 17.5λ respectively, and the widths are all 15λ.

[0021] The antenna array layer 1 is composed of 1*8 antenna units arranged linearly, the spacing between each antenna unit is 0.6λ-0.7λ, and the overall distribution is symmetrical; wherein λ is the wavelength of the electromagnetic wave of the array antenna; each linear unit includes a feed line 11, and the feed line 11 is composed of GCPW on the antenna array layer 1 and is distributed in a U-shaped routing; one end of the feed line 11 is connected to a rectangular transmission line 12, and one side of the rectangular transmission line 12 is connected to a plurality of radiation units, and the radiation units of this embodiment include a first radiation unit 13, a second radiation unit 14, a third radiation unit 15 and a fourth radiation unit 16; the rectangular transmission line 12 is provided with a first rectangular groove 121, a second rectangular groove 122 and a third rectangular groove 123, forming an H-type feeding network for feeding the sides of a plurality of radiation units.

[0022] The present application can change the structure of the H-type feeding network by adjusting the size of the three rectangular grooves, thereby changing the current ratio distributed to the four radiating units. Compared with the traditional power-dividing parallel feeding network, this transmission structure can also control the current ratio distributed to the four radiating units to change the amplitude and phase of the radiating units, forming a uniform beam width at different frequencies, thereby achieving a wide beam, and compared with the parallel feeding network structure, it is simpler, has high space utilization, and high radiation efficiency.

[0023] Specifically, the size of the rectangular transmission line 12 is (2.2λ-2.4λ)*0.125λ; the size of the first rectangular groove 121 is (0.3λ-0.4λ)*0.075λ; the size of the second rectangular groove 122 is (0.16λ-0.18λ)*0.075λ; the size of the third rectangular groove 123 is (0.2λ-0.4λ)*0.075λ; where λ is the wavelength of the electromagnetic wave of the array antenna.

[0024] Reference Figure 5 For the radiation unit, it includes a rectangular patch antenna, which is connected to the rectangular transmission line 12 through an L-shaped connecting line 132.

[0025] The rectangular patch antenna is also symmetrically provided with two fourth rectangular grooves 133, which are distributed on both sides of the connection between the L-shaped connecting line 132 and the rectangular patch antenna; the size of the rectangular patch antenna is (0.25λ-0.29)λ*0.275λ, and the size of the fourth rectangular groove 133 is (0.055λ-0.15λ)*(0.0375λ-0.0575λ); wherein λ is the wavelength of the electromagnetic wave of the array antenna.

[0026] In addition, a transition microstrip is provided between the L-shaped connecting line and the rectangular transmission line 12; the size of the transition microstrip is (0.13λ-0.24λ)*(0.03λ-0.075λ); wherein λ is the wavelength of the electromagnetic wave of the array antenna. In this embodiment, the L-shaped connecting line 132 of the first radiating unit 13 is connected to the rectangular transmission line 12 through the first transition microstrip 131, and the L-shaped connecting line 132 of the second radiating unit 14 is connected to the rectangular transmission line 12 through the second transition microstrip 141. The microstrip line side feeding structure of the radiating unit is realized by the L-shaped connecting line and the transition microstrip line. This microstrip line side feeding connects the radiating unit with the serial side feeding structure, thereby realizing miniaturization.

[0027] Reference Figure 2 , Figure 3 and Figure 6 , a U-shaped passage consisting of a top-layer through hole 17 is respectively arranged on both sides of each feed line 11, the integrated waveguide layer 2 is provided with a waveguide through hole 21 matching the top-layer through hole 17, and the ground layer 3 is provided with a ground through hole 31 matching the waveguide through hole 21, so as to realize that the corresponding top-layer through hole 17, waveguide through hole 21 and ground through hole 31 are interconnected. The top-layer through hole 17, waveguide through hole 21 and ground through hole 31 are of the same size and correspond to each other, and together with the feed line (11) composed of GCPW, form a waveguide structure.

[0028] The radius of the waveguide through hole 21 is (0.03λ-0.06λ), the lateral spacing is (0.064λ-0.255λ), the longitudinal spacing is (0.08λ-0.125λ), and the height is 0.04λ-0.05λ; the spacing between the top through hole 17 and the feed line 11 is 0.12λ-0.14λ; where λ is the wavelength of the electromagnetic wave of the array antenna.

[0029] Figure 7 Input port return loss parameters for array antennas Result graph. Return loss parameters of array antenna input port In the 75-85GHz frequency band, The value is less than 10dB, achieving broadband.

[0030] Figure 8 The beam width result diagram of the E-plane of the array antenna is shown in Figure 2. The beam width of the E-plane of the array antenna increases from -22° to 24° at 76 GHz, 78 GHz, and 80 GHz, achieving a wide beam.

[0031] Fig. 9 The beam width result diagram of the array antenna H plane is as follows. The beam width of the array antenna H plane is from -40° to 40° at 76GHz and 81GHz, and from -18° to 24° at 78GHz, achieving a wide beam.

[0032] Fig.10 The following are the imaging results of other wide beam antennas and the array antenna of the present invention in the microwave imaging system. It can be seen that the broadband and E-plane and H-plane wide beam performance of the array antenna of the present invention make the imaging results clearer and have higher resolution than the traditional single-plane wide beam antenna.

Claims

1. An etched microstrip line wide bandwidth beam patch array antenna based on side feeding, characterized in that: It comprises an antenna array layer (1), an integrated waveguide layer (2) and a ground layer (3) which are arranged in sequence; The antenna array layer (1) is composed of a plurality of antenna units arranged linearly, wherein the linear units include a feed line (11), one end of the feed line (11) is connected to a rectangular transmission line (12), and one side of the rectangular transmission line (12) is connected to a plurality of radiation units; the rectangular transmission line (12) is provided with a first rectangular groove (121), a second rectangular groove (122), and a third rectangular groove (123), forming an H-type feeding network for side feeding of the plurality of radiation units.

2. The etched microstrip line wide bandwidth beam patch array antenna based on side feeding according to claim 1, characterized in that: The size of the rectangular transmission line (12) is (2.2λ-2.4λ)*0.125λ; the size of the first rectangular groove (121) is (0.3λ-0.4λ)*0.075λ; the size of the second rectangular groove (122) is (0.16λ-0.18λ)*0.075λ; the size of the third rectangular groove (123) is (0.2λ-0.4λ)*0.075λ; wherein λ is the wavelength of the electromagnetic wave of the array antenna.

3. The etched microstrip line wide bandwidth beam patch array antenna based on side feeding according to claim 1, characterized in that: The radiation unit comprises a rectangular patch antenna, and the rectangular patch antenna is connected to the rectangular transmission line (12) via an L-shaped connecting line (132).

4. The etched microstrip line wide bandwidth beam patch array antenna based on side feeding according to claim 3, characterized in that: The rectangular patch antenna is also symmetrically provided with two fourth rectangular grooves (133), which are distributed on both sides of the connection between the L-shaped connecting line (132) and the rectangular patch antenna; the size of the rectangular patch antenna is (0.25λ-0.29)λ*0.275λ, and the size of the fourth rectangular groove (133) is (0.055λ-0.15λ)*(0.0375λ-0.0575λ); wherein λ is the wavelength of the electromagnetic wave of the array antenna.

5. The etched microstrip line wide bandwidth beam patch array antenna based on side feeding according to claim 3, characterized in that: A transition microstrip is also provided between the L-shaped connecting line (132) and the rectangular transmission line (12); the transition microstrip has a size of (0.13λ-0.24λ)*(0.03λ-0.075λ); wherein λ is the wavelength of the electromagnetic wave of the array antenna.

6. The etched microstrip line wide bandwidth beam patch array antenna based on side feeding according to claim 1, characterized in that: The feed line (11) is formed of GCPW on the antenna array layer (1) and is distributed in a U-shaped routing pattern.

7. The etched microstrip line wide bandwidth beam patch array antenna based on side feeding according to claim 1, characterized in that: A plurality of top-layer through holes (17) are provided on both sides of the feed line (11), the integrated waveguide layer (2) is provided with a waveguide through hole (21) matching the top-layer through hole (17), and the grounding layer (3) is provided with a grounding through hole (31) matching the waveguide through hole (21), so that the corresponding top-layer through holes (17), the waveguide through holes (21) and the grounding through holes (31) are connected to each other.

8. The etched microstrip line wide bandwidth beam patch array antenna based on side feeding according to claim 7, characterized in that: The radius of the waveguide through hole (21) is (0.03λ-0.06λ), the lateral spacing is (0.064λ-0.255λ), the longitudinal spacing is (0.08λ-0.125λ), and the height is 0.04λ-0.05λ; the spacing between the top through hole (17) and the feed line (11) is 0.12λ-0.14λ; wherein λ is the wavelength of the electromagnetic wave of the array antenna.

9. The etched microstrip line wide bandwidth beam patch array antenna based on side feeding according to claim 1, characterized in that: The spacing between the antenna units is 0.6λ-0.7λ, and the overall distribution is symmetrical; where λ is the wavelength of the electromagnetic wave of the array antenna.

10. The etched microstrip line wide bandwidth beam patch array antenna based on side feeding according to claim 1, characterized in that: The array antenna operates in the frequency band of 75GHz-85GHz, the beam width of the E plane ranges from -22° to 24°, and the beam width of the H plane ranges from -40° to 40°.

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