Ultra-wideband coupled patch antenna and design method thereof

Abstract

The application discloses an ultra-wideband coupled patch antenna and a design method thereof, which comprises a top conductive layer, a ground plate and a bottom conductive layer; the top conductive layer comprises two driving patches, and two first coupled patches are arranged in parallel on the outer side of each driving patch; two second coupled patches are arranged on the front and back sides of each driving patch; the inner sides of the two driving patches are wrapped with two third coupled patches arranged vertically; in order to ensure the stability of the radiation pattern, only the driving patches and the second coupled patches are used as impedance adjustment patches; the ground plate is provided with a hole aperture coupling feed point, and the hole aperture coupling feed point is located at the center of the antenna; the bottom conductive layer comprises a bottom microstrip line, the bottom microstrip line is converted into a two-branch feed structure, and the two-branch feed structure transmits electromagnetic energy to the driving patches through the hole aperture coupling feed point. The application is based on a simple three-layer dielectric structure of coupling effect, and can reduce the processing cost and complexity of the antenna.

Description

Technical Field

[0001] This invention belongs to the field of radar communication, specifically relating to an ultra-wideband coupled patch antenna and its design method. Background Technology

[0002] With the current development of millimeter-wave communication systems and ultra-wideband imaging systems, greater demands are being placed on antenna bandwidth, cost, size, and manufacturing complexity. Complex ultra-wideband systems often require antennas to have a smaller size, lower manufacturing cost, and lower complexity while meeting bandwidth requirements. Currently, most existing ultra-wideband antennas achieve ultra-wideband characteristics by using multi-layer PCBs, multiple parasitic patches, complex feeding structures, and altered transmission line shapes. However, it is rare to find antenna elements that possess ultra-wideband characteristics while maintaining a simple antenna structure. Summary of the Invention

[0003] To address the issue of the complex structure of current ultra-wideband antennas in the millimeter-wave band, this invention proposes an ultra-wideband coupled patch antenna and its design method. It is an ultra-wideband antenna unit with a simple three-layer dielectric structure based on coupling, which can reduce antenna manufacturing costs and complexity.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] An ultra-wideband coupled patch antenna includes a top conductive layer, a ground plane, and a bottom conductive layer. The top conductive layer includes two driving patches, with two parallel first coupling patches on the outer side of each driving patch, and two second coupling patches placed on the front and rear sides of each driving patch. Two vertically arranged third coupling patches are wrapped around the inner sides of the two driving patches. To ensure the stability of the radiation pattern, only the driving patches and second coupling patches are used as impedance adjustment patches. The ground plane has an aperture coupling feed point located at the center of the antenna. The bottom conductive layer includes a bottom microstrip line, which is converted into a two-branch feed structure. The two-branch feed structure transmits electromagnetic energy to the driving patches through the aperture coupling feed point. The bottom microstrip line connects the two-branch feed structures and excites the central portions of the two driving patches respectively through the aperture coupling feed point. A first dielectric layer and a second dielectric layer are disposed between the top conductive layer and the ground plane, and a third dielectric layer is disposed between the ground plane and the bottom conductive layer.

[0006] Furthermore, the first dielectric layer, the second dielectric layer, and the third dielectric layer are all made of dielectric substrate and high-frequency materials; the relative permittivity of the first dielectric layer is 3.7 and the thickness is 0.168 mm; the relative permittivity of the second dielectric layer is 3.52 and the thickness is 0.102 mm; the relative permittivity of the third dielectric layer is 3.03 and the thickness is 0.127 mm.

[0007] Furthermore, the top conductive layer, ground plane, and bottom conductive layer are all made of 0.5 ounces of electrolytic copper.

[0008] This invention also provides a design method for an ultra-wideband coupled patch antenna. First, a model is established comprising a first dielectric layer, a second dielectric layer, a third dielectric layer, a ground plane, an aperture-coupled feed point, a bottom microstrip line, a two-branch feed structure, a driving patch, and an inner third coupled patch. The resonant frequency is then initially adjusted. After adjusting the resonant frequency to the required frequency range, second coupled patches are added to the front and rear sides of the driving patch, and the resonant frequency is adjusted again. Finally, third coupled patches are added to both sides of the driving patch, and the resonant frequency and antenna pattern are optimized and adjusted according to the various structural parameters of the antenna.

[0009] Furthermore, the structural parameters include: the length of the two-branch feeding structure, the aperture width of the aperture coupling feed point, the width of the driving patch, the gap between the driving patch and the third coupling patch, the length of the second coupling patch, and the gap between the third coupling patch and the driving patch.

[0010] Beneficial effects:

[0011] This invention utilizes aperture-coupled feeding and coupling patches to broaden the bandwidth, achieving ultra-wideband performance for a single antenna element while simplifying fabrication, thus reducing the manufacturing cost of ultra-wideband antennas. It provides a set of optimal design parameters to achieve the best bandwidth and achievable gain. At the same time, the small size of a single antenna element allows for good antenna array formation and effective application in high-gain scenarios. Attached Figure Description

[0012] Figure 1 This is a three-dimensional structural schematic diagram of the ultra-wideband coupled patch antenna of the present invention;

[0013] Figure 2a , Figure 2b , Figure 2c This is a top view of the antenna's top conductive layer, ground plane, and bottom conductive layer; where... Figure 2a This is a schematic diagram of the top-level radiating patch structure. Figure 2b This is a schematic diagram of the coupling hole for the ground plane. Figure 2c This is a schematic diagram of the bottom-level feeder cable;

[0014] Figure 3 The diagram shows the achievable gain and S11 return loss parameters for an ultra-wideband coupled patch antenna.

[0015] Figure 4a , Figure 4b , Figure 4c , Figure 4d The main polarization and cross-polarization patterns of the antenna's E-plane and H-plane are shown; where Figure 4a For the E side (68GHz), Figure 4b For H-plane (68GHz), Figure 4c For the E side (80GHz), Figure 4d For H-plane (80GHz);

[0016] Figure 5 This is a schematic diagram of the bottom-layer feeding structure for a 1x4 antenna array.

[0017] Figure 6 Plot of achievable gain and S11 return loss parameters for a 1x4 antenna array;

[0018] Figure 7a , Figure 7b , Figure 7c , Figure 7d , Figure 7e , Figure 7f , Figure 7g This is a graph showing the effect of the parameters of an ultra-wideband coupled patch antenna on its input impedance; where, Figure 7a For L s The effect of parameter changes on antenna input impedance Figure 7b For w a The effect of parameter changes on antenna input impedance Figure 7c For l r The effect of parameter changes on antenna input impedance Figure 7d For w r The effect of parameter changes on antenna input impedance Figure 7e The effect of changes in parameter s1 on the antenna input impedance. Figure 7f This describes the effect of changes in the s4 parameter on the antenna input impedance. Figure 7g For l f The effect of parameter changes on antenna input impedance. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0020] like Figure 1As shown, the ultra-wideband coupled patch antenna of the present invention includes a top conductive layer, a ground plane 6, and a bottom conductive layer. Preferably, the distance between the top conductive layer and the ground plane is 0.27 mm, and the distance between the ground plane and the bottom conductive layer is 0.127 mm. The top conductive layer includes two driving patches 1, with two parallel first coupling patches 2 on the outer side of each driving patch 1. Two second coupling patches 3 are placed on the front and rear sides of each driving patch 1, and two vertically arranged third coupling patches 4 are wrapped around the inner side of each driving patch 1. The ground plane 6 has an aperture coupling feed point 5 located at the center of the antenna. The bottom microstrip line 7 of the bottom conductive layer is converted into a two-branch feed structure 8, which transmits electromagnetic energy to the driving patches 1 through the aperture coupling feed point 5. The bottom conductive layer is made of copper foil.

[0021] To ensure the stability of the radiation pattern, only the driving patch 1 and the second coupling patch 3 are used as the main patches for impedance adjustment. To increase the bandwidth, the aperture coupling feed point 5, the bottom microstrip line 7, and the two-branch feed structure 8, which serve as the bottom feed section, adopt a microstrip branch feed coupling structure. The bottom microstrip line 7 connects the two branch feed structures 8 and excites the central parts of the two driving patches 1 respectively through an aperture coupling feed point 5.

[0022] The top conductive layer, ground plane 6, and bottom conductive layer can be made of 0.5 ounces of electrolytic copper, but are not limited to electrolytic copper. The first dielectric layer 9 and the second dielectric layer 10 are located between the top conductive layer and the ground plane 6, and the third dielectric layer 11 is located between the ground plane 6 and the bottom conductive layer.

[0023] Table 1. Coupled Antenna Structure Parameters

[0024]

[0025]

[0026] like Figure 2a , Figure 2b , Figure 2c As shown, an embodiment of the specific dimensions of each part of the ultra-wideband coupled patch antenna of the present invention is listed in Table 1. w and l are the width and length of the third coupling patch 4, respectively. r and l r These are the width and length of driver patch 1, respectively. side and l side These are the width and length of the first coupling patch 2, respectively. f and l fThese represent the width and length of the second coupling patch 3, respectively; s1 is the gap between the driving patch 1 and the third coupling patch 4; s2 is the gap between the two third coupling patches 4; s3 is the gap between the driving patch 1 and the first coupling patch 2; s4 is the gap between the driving patch 1 and the second coupling patch 3; w gnd It is the width of the floor 6, L a and w a These are the length and width of aperture coupling feed point 5, w1 and L, respectively. s L l These are the width, length, and spacing between the two branches of the two-branch feed structure 8. Table 1 shows the optimized structural parameters, which comprehensively consider the influence of each coupling patch and achieve a trade-off between bandwidth and achievable gain in the current frequency band. Figure 2c The 50 ohm indicates that the input impedance of the underlying microstrip line 7 is 50 ohms in the current frequency band.

[0027] like Figure 1 As shown, the first dielectric layer 9, the second dielectric layer 10, and the third dielectric layer 11 are all made of high-frequency materials: the first dielectric layer 9 is Rogers 4350B with a thickness of 0.168 mm; the second dielectric layer 10 is Rogers 4450F with a thickness of 0.102 mm; and the third dielectric layer 11 is Rogers 3003 with a thickness of 0.127 mm.

[0028] like Figure 3 As shown, the ultra-wideband coupled patch antenna of this invention has a -10dB impedance matching bandwidth of 64.5 to 83.6 GHz (relative bandwidth of 25.8% at 74.5 GHz). Gains exceeding 6.5 dBi can be achieved between 65 GHz and 84 GHz.

[0029] like Figure 4a , Figure 4b , Figure 4c , Figure 4d The antenna's main polarization and cross-polarization radiation patterns are shown at 68 GHz and 80 GHz. The main polarization radiation patterns are very rounded, with cross-polarization levels of approximately -100 dB and -20 dB in the E-plane and H-plane, respectively. Figure 4a For the E side (68GHz), Figure 4b For H-plane (68GHz), Figure 4c For the E side (80GHz), Figure 4d For H-plane (80GHz).

[0030] like Figure 5 As shown, a feeding structure 12 for a 1×4 antenna array is constructed based on the ultra-wideband coupled patch antenna of the present invention. The feeding structure 12 is located in Figure 1The middle and bottom conductive layers employ two-stage 3dB power dividers, with one segment connected to the two-branch feed structure 8. The spacing between each ultra-wideband coupled patch antenna is 3.5 mm.

[0031] like Figure 6 As shown, the antenna array has a -10dB impedance bandwidth of approximately 23.7 GHz (64.6-88.4 GHz) or 31% relative bandwidth, and can achieve a gain of over 11 dBi.

[0032] A general design method for this ultra-wideband coupled patch antenna is presented. First, a model is established for the first dielectric layer 9, the second dielectric layer 10, the third dielectric layer 11, the ground plane 6, the aperture coupling feed point 5, the bottom microstrip line 7, the two-branch feed structure 8, the driving patch 1, and the inner third coupling patch 4. The resonant frequency is initially adjusted. After adjusting the resonant frequency to the required frequency range, second coupling patches 3 are added to the front and rear sides of the driving patch 1, and the resonant frequency is adjusted again. Finally, first coupling patches 2 are added to both sides of the driving patch, and the resonant frequency and antenna pattern are optimized and adjusted according to the structural parameters proposed in this invention.

[0033] The following are the main effects of different antenna parameters on impedance matching as presented in this invention.

[0034] like Figure 6 As shown, this invention presents the main effects of various antenna parameters on impedance matching. Figure 6 From left to right, there are three main impedance resonance peaks: left resonance peak P1, middle resonance peak P2, and right resonance peak P3, which affect impedance matching. The left resonance peak P1 is mainly excited by the driving patch 1. The middle resonance peak P2 is mainly excited by the two-branch feed structure 8 and the aperture coupling feed point 5. The right resonance peak P3 is caused by the second coupling patch 3.

[0035] like Figure 7a As shown, the length Ls of the two-branch feed structure 8 plays a crucial role in impedance matching. It has a significant impact on the three resonant peaks and should be the first parameter to be adjusted.

[0036] like Figure 7b As shown, the width Wa of the aperture-coupled feed point 5 can be used to adjust the middle resonant peak P2 and the right resonant peak P3. The aperture length La of the aperture-coupled feed point 5 is recommended to be longer than the edges of the two drive patches 1. In this case, it has almost no impact on impedance matching.

[0037] like Figure 7c , Figure 7d , Figure 7e As shown, the width Wr of the driving patch 1 and the gap s1 between the driving patch 1 and the third coupling patch 4 may have a greater impact on the resonant impedance than the length lr of the driving patch 1. The width Wr and the gap s1 of the driving patch 1 have an approximate regulating effect on the impedance.

[0038] like Figure 7f , Figure 7g As shown, the length lf of the second coupling patch 3 and the gap s4 between the third coupling patch 3 and the driving patch 1 have almost no effect on the left resonant peak P1, but have a great influence on the middle resonant peak P2 and the right resonant peak P3.

[0039] The first coupling patch 2 and the third coupling patch 4 can also excite resonant peaks to improve impedance matching performance. However, the current distribution of the two coupling patches is opposite to the driving patch current, which will degrade the antenna radiation performance. Therefore, while ensuring bandwidth, the first coupling patch 2 and the third coupling patch 4 can be pulled out of the operating frequency range, which only has a slight effect on the left resonant peak P1, the middle resonant peak P2, and the right resonant peak P3.

[0040] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ultra-wideband coupled patch antenna, characterized in that: The antenna comprises a top conductive layer, a ground plane, and a bottom conductive layer. The top conductive layer includes two driving patches, with two parallel first coupling patches on the outer side of each driving patch. Two second coupling patches are placed on the front and rear sides of each driving patch. Two vertically arranged third coupling patches are wrapped around the inner sides of the two driving patches. To ensure the stability of the radiation pattern, only the driving patches and second coupling patches are used for impedance adjustment. The ground plane has an aperture coupling feed point located at the center of the antenna. The bottom conductive layer contains a bottom microstrip line, which is converted into a two-branch feed structure. This two-branch feed structure transmits electromagnetic energy to the driving patches through the aperture coupling feed point. The bottom microstrip line connects the two-branch feed structures and excites the central portions of the two driving patches through the aperture coupling feed point. A first dielectric layer and a second dielectric layer are disposed between the top conductive layer and the ground plane from top to bottom, and a third dielectric layer is disposed between the ground plane and the bottom conductive layer. The first dielectric layer, the second dielectric layer, and the third dielectric layer are all made of high-frequency materials; the relative permittivity of the first dielectric layer is 3.7 and the thickness is 0.168 mm; the relative permittivity of the second dielectric layer is 3.52 and the thickness is 0.102 mm; the relative permittivity of the third dielectric layer is 3.03 and the thickness is 0.127 mm.

2. The ultra-wideband coupled patch antenna according to claim 1, characterized in that: The top conductive layer, ground plane, and bottom conductive layer are all made of 0.5 ounces of electrolytic copper.

3. A design method for an ultra-wideband coupled patch antenna according to any one of claims 1-2, characterized in that, First, models of the first dielectric layer, second dielectric layer, third dielectric layer, ground plane, aperture coupling feed point, bottom microstrip line, two-branch feed structure, driving patch, and inner third coupling patch are established, and the resonant frequency is initially adjusted. After adjusting the resonant frequency to the required frequency range, second coupling patches are added to the front and rear sides of the driving patch, and the resonant frequency is adjusted again. Finally, third coupling patches are added to both sides of the driving patch, and the resonant frequency and antenna pattern are optimized and adjusted according to the various structural parameters of the antenna.

4. The design method according to claim 3, characterized in that, The structural parameters include: the length of the two-branch feeding structure, the aperture width of the aperture coupling feed point, the width of the driving patch, the gap between the driving patch and the third coupling patch, the length of the second coupling patch, and the gap between the third coupling patch and the driving patch.

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