Low cross polarization broadband conformal microstrip antenna

Abstract

The utility model belongs to the technical field of antennas, and provides a low cross polarization broadband conformal microstrip antenna, which comprises a metal carrier, a foam layer, a dielectric substrate, a microstrip radiation patch, a metal bonding pad and a feed coaxial line, and is characterized in that the foam layer is conformally arranged on the upper surface of the metal carrier; the dielectric substrate is conformally arranged on the upper surface of the foam layer, the microstrip radiation patch is arranged on the upper surface of the dielectric substrate, and a through hole is formed in the microstrip radiation patch; the metal bonding pad is arranged in the through hole, and a gap is formed between the outer periphery of the metal bonding pad and the inner periphery of the through hole; the two feed coaxial lines sequentially comprise an inner conductor, an insulating layer and an outer conductor from inside to outside, the outer conductor is connected with the metal carrier, and the inner conductor is connected with the metal bonding pad. By adjusting the height of the foam layer, the impedance matching performance of the antenna can be adjusted; a gap is formed between the microstrip radiation patch and the metal bonding pad to form coupling feed, the input impedance and the resonant frequency of the antenna can be adjusted by adjusting the size of the gap, and the design flexibility is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of antennas, and particularly relates to a low cross-polarization wide-band conformal microstrip antenna. Background Art

[0002] With the increasingly strict requirements for mobile communication standards in various countries, the spectrum resources are becoming increasingly scarce, and users are constantly putting forward new requirements for transmission rate, working bandwidth, etc. Antennas need to develop towards wide bands, so wide-band technology has become a research hotspot in the past decade or so. Due to its simple structure, low profile, easy polarization control, wide beam coverage range, etc., and the antenna can be integrated with the microstrip circuit, and the industrial manufacturing is simple, the microstrip antenna is widely used in various fields of measurement and communication. However, the microstrip antenna is a typical resonant antenna that works through the coupling resonance between the radiation patch and the ground plane. Therefore, the bandwidth of the microstrip antenna is relatively narrow. Usually, the microstrip antenna can increase the thickness of the dielectric substrate, reduce the Q value of the microstrip antenna, and broaden the bandwidth.

[0003] When the dielectric substrate is relatively thick, coaxial probe feeding will generate a relatively high cross-polarization field, resulting in enhanced cross-polarization radiation of the antenna. If the antenna radiates waves of non-predetermined polarization in addition to the waves of the predetermined polarization, the former is called the main polarization, and the latter is called the cross-polarization or parasitic polarization; the cross-polarization component will interfere with the main polarization component of the antenna, affect the performance of the antenna, and bring inconvenience to the communication system. The cross-polarization component will interfere with the main polarization of the antenna, reduce the main radiation directivity of the antenna, and affect the radiation performance of the antenna; at the same time, for a large-scale phased array system, a high cross-polarization will limit the large-angle beam scanning of the array antenna. Summary of the Utility Model

[0004] Aiming at the defects in the prior art, the utility model provides a low cross-polarization wide-band conformal microstrip antenna to solve the problems of narrow bandwidth and insufficient cross-polarization suppression of the current microstrip antenna.

[0005] A low cross-polarization wide-band conformal microstrip antenna provided by the utility model includes:

[0006] A metal carrier;

[0007] A foam layer, conformally arranged on the upper surface of the metal carrier;

[0008] A dielectric substrate, conformally arranged on the upper surface of the foam layer,

[0009] A microstrip radiation patch, arranged on the upper surface of the dielectric substrate, and through holes are formed in the microstrip radiation patch;

[0010] A metal pad, arranged in the through hole, and there is a gap between the outer peripheral edge of the metal pad and the inner peripheral edge of the through hole;

[0011] The two feeding coaxial lines sequentially include an inner conductor, an insulating layer, and an outer conductor from the inside to the outside. The outer conductor is connected to the metal carrier, and the inner conductor is connected to the metal pad.

[0012] As can be seen from the above technical solution, a low cross-polarization wide-band conformal microstrip antenna provided by the present utility model is supported by a foam layer on a dielectric substrate. By adjusting the height of the foam layer, the impedance matching performance of the antenna can be adjusted; there is a gap between the microstrip radiation patch and the metal pad, forming a coupled feeding form. By adjusting the size of the gap, without changing the length and width of the patch, the input impedance and resonant frequency of the antenna can be adjusted, increasing the design flexibility.

[0013] Optionally, a first arc surface is formed on the upper surface of the metal carrier, and a second arc surface is formed on the upper surface of the foam layer. The radius of the first arc surface is greater than the radius of the second arc surface.

[0014] Optionally, the gap is annular. By adjusting the width of the annular gap, without changing the length and width of the patch, the input impedance and resonant frequency of the antenna can be adjusted.

[0015] Optionally, the feeding coaxial lines are differentially fed. Compared with the traditional single-port microstrip antenna form, its cross-polarization component is significantly reduced, and the main polarization far-field radiation performance is basically the same as that of the single-port fed microstrip antenna, maintaining the high radiation performance advantages of the traditional microstrip antenna.

[0016] Optionally, the foam layer is made of PMI material. The low-density PMI material is used to support the dielectric substrate, forming a cavity between the dielectric substrate and the metal carrier. By adjusting the thickness of the PMI, that is, adjusting the depth of the cavity, the impedance matching of the antenna in a relatively wide frequency band can be achieved.

[0017] Adopting the above technical solution, the present application has at least the following technical effects:

[0018] (1) For the low cross-polarization wide-band conformal microstrip antenna provided by the present utility model, the dielectric substrate is supported by the foam layer, forming a cavity between the dielectric substrate and the metal carrier. By adjusting the height of the foam layer, the impedance matching performance of the antenna can be adjusted; there is a gap between the microstrip radiation patch and the metal pad, forming a coupled feeding form. By adjusting the size of the gap, without changing the length and width of the patch, the input impedance and resonant frequency of the antenna can be adjusted, increasing the design flexibility;

[0019] (2) The two feeding coaxial lines in the present utility model are differentially fed. Compared with the traditional single-port microstrip antenna form, its cross-polarization component is significantly reduced, and the main polarization far-field radiation performance is basically the same as that of the single-port fed microstrip antenna, maintaining the high radiation performance of the traditional microstrip antenna. Brief Description of the Drawings

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to actual scale.

[0021] Figure 1 The front view of a low cross-polarization wideband conformal microstrip antenna provided by an embodiment of the present invention;

[0022] Figure 2 For Figure 1 The top view of a low cross-polarization wideband conformal microstrip antenna as shown;

[0023] Figure 3 The standing wave curve graph of a low cross-polarization wideband conformal microstrip antenna provided by an embodiment of the present invention;

[0024] Figure 4 The main polarization and its cross-polarization curve graphs of a low cross-polarization wideband conformal microstrip antenna provided by an embodiment of the present invention in the azimuth plane and elevation plane at 5.4 GHz;

[0025] Figure 5 The main polarization and its cross-polarization curve graphs of a low cross-polarization wideband conformal microstrip antenna provided by an embodiment of the present invention in the azimuth plane and elevation plane at 7 GHz;

[0026] Figure 6 The main polarization and its cross-polarization curve graphs of a low cross-polarization wideband conformal microstrip antenna provided by an embodiment of the present invention in the azimuth plane and elevation plane at 8 GHz.

[0027] Reference Numerals:

[0028] 1 - Metal carrier; 2 - Foam layer; 3 - Dielectric substrate; 4 - Microstrip radiation patch; 5 - Metal pad; Feeding coaxial cable; 61 - Inner conductor; 62 - Insulating layer; 63 - Outer conductor. Detailed Embodiments

[0029] The following will describe in detail the embodiments of the technical solutions of the present invention in conjunction with the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and thus are only examples and cannot be used to limit the protection scope of the present invention.

[0030] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should have the ordinary meanings understood by those skilled in the art to which the present invention belongs.

[0031] The terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. In the description of the present utility model, "a plurality of" means more than two unless otherwise specifically defined.

[0032] As Figure 1-2 shown, a low cross-polarization wideband conformal microstrip antenna provided in this embodiment includes a metal carrier 1, a foam layer 2, a dielectric substrate 3, a microstrip radiation patch 4, a metal pad 5, and two feeding coaxial lines 6. The foam layer 2 is conformally disposed on the upper surface of the metal carrier; the dielectric substrate 3 is conformally disposed on the upper surface of the foam layer 2, the microstrip radiation patch 4 is disposed on the upper surface of the dielectric substrate 3, and through holes are formed in the microstrip radiation patch 4; the metal pad 5 is disposed in the through holes, and there is a gap between the outer peripheral edge of the metal pad 5 and the inner peripheral edge of the through holes; the two feeding coaxial lines 6 sequentially include an inner conductor 61, an insulating layer 62, and an outer conductor 63 from the inside to the outside. The outer conductor 63 is connected to the metal carrier 1, and the inner conductor 61 is connected to the metal pad 5.

[0033] In this embodiment, the foam layer 2 supports the dielectric substrate 3. Based on adjusting the height of the foam layer 2, the impedance matching performance of the antenna can be adjusted; there is a gap between the microstrip radiation patch 4 and the metal pad 5, forming a coupled feeding form. By adjusting the size of the gap, the input impedance and resonance frequency of the antenna can be adjusted without changing the length and width of the patch, increasing the design flexibility.

[0034] Specifically as Figure 1 shown, the outer conductor 63 is connected to the bottom of the metal carrier 1, the insulating layer 62 in the metal carrier 1 is connected to the metal carrier 1, and the inner conductor 61 is connected to the foam layer 2.

[0035] Specifically, in this embodiment, the thickness of the dielectric substrate 3 is 10 mils, and a Rogers RO4350 high-frequency single-layer dielectric board is used.

[0036] In a possible implementation manner, the upper surface of the metal carrier 1 forms a first arc surface, and the upper surface of the foam layer 2 forms a second arc surface. The radius of the first arc surface is greater than the radius of the second arc surface.

[0037] Optionally, the gap is annular. By adjusting the width of the annular gap, the input impedance and resonance frequency of the antenna can be adjusted without changing the length and width of the patch.

[0038] Optionally, the amplitudes of the two feeding coaxial lines 6 are equal, and the feeding coaxial lines 6 are arranged in mirror symmetry, with a phase difference of 180° to form a differentially-fed form with structural symmetry, suppressing the cross-polarization component. The current on the microstrip antenna is symmetric about the perpendicular bisector of the two feeding coaxial lines. Compared with the traditional single-port microstrip antenna form, its cross-polarization component is significantly reduced, and the main-polarization far-field radiation performance is basically the same as that of the single-port fed microstrip antenna, maintaining the high radiation performance of the traditional microstrip antenna.

[0039] Optionally, the foam layer 2 is made of PMI material. In this embodiment, a low-density PMI material is used to support the dielectric substrate 3, so as to form a cavity between the dielectric substrate 3 and the metal carrier 1. By adjusting the thickness of the PMI foam, that is, adjusting the depth of the cavity formed between the metal carrier 1 and the dielectric substrate 3, impedance matching of the antenna in a relatively wide frequency band is achieved.

[0040] In a possible implementation manner, the radius of the first arc surface is 25 mm, the radius of the second arc surface is 12 mm, the width l1 of the microstrip radiation patch is 15.6 mm, the length l2 is 7 mm, the width l3 of the annular slot is 0.41 mm, the height l4 of the foam layer is 4.8 mm, and the diameter l5 of the inner conductor is 0.5 mm.

[0041] Based on this, the standing wave curve of the low cross-polarization wide-band conformal microstrip antenna provided in this embodiment is as Figure 3 shown. It can be obtained from Figure 3 that the antenna bandwidth covers 5.4 GHz to 8 GHz, and the relative bandwidth is 38.8%, achieving good wide-band impedance matching performance.

[0042] Figure 4 This is the main polarization and its cross-polarization curves of the low cross-polarization wide-band conformal microstrip antenna provided in this embodiment at 5.4 GHz in the azimuth plane and elevation plane. Among them, the main polarization in the azimuth plane is the Phi = 90° GainPhi component, and its cross polarization is the Phi = 90° GainTheta component. It can be obtained from Figure 4 that in the azimuth plane and elevation plane, the difference between its main polarization and cross polarization is 72.8 dB. The gain in the main radiation direction is 4.2 dB. It shows that an ultra-low cross-polarization suppression effect is achieved without affecting the main radiation direction.

[0043] Figure 5 This is the main polarization and its cross-polarization curves of the low cross-polarization wide-band conformal microstrip antenna provided in this embodiment at 7 GHz in the azimuth plane and elevation plane. Among them, the main polarization in the azimuth plane is the Phi = 90° GainPhi component, and its cross polarization is the Phi = 90° GainTheta component. It can be obtained from Figure 5It can be obtained that in the azimuth plane and elevation plane, the difference between its co-polarization and cross-polarization is 73.8 dB. The gain in the main radiation direction is 6.9 dB. It shows that an ultra-low cross-polarization suppression effect is achieved without affecting the main radiation direction.

[0044] Figure 6 The co-polarization and cross-polarization curves of the azimuth plane and elevation plane of the low cross-polarization broadband conformal microstrip antenna provided in this embodiment at 8 GHz are shown. The co-polarization in the azimuth plane is the Phi = 90° GainPhi component, and its cross-polarization is the Phi = 90° GainTheta component. From Figure 6 It can be obtained that in the azimuth plane and elevation plane, the difference between its co-polarization and cross-polarization is 58.9 dB, and the gain in the main radiation direction is 7.1 dB. It shows that an ultra-low cross-polarization suppression effect is achieved without affecting the main radiation direction.

[0045] In the description of the present invention, a large number of specific details are set forth. However, it can be understood that the embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and technologies are not shown in detail so as not to obscure the understanding of this specification.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A low cross-polarization wideband conformal microstrip antenna, characterized in that, Comprising: A metal carrier; A foam layer conformally disposed on the upper surface of the metal carrier; A dielectric substrate conformally disposed on the upper surface of the foam layer, A microstrip radiation patch disposed on the upper surface of the dielectric substrate, and through holes are formed in the microstrip radiation patch; A metal pad disposed in the through holes, and there is a gap between the outer peripheral edge of the metal pad and the inner peripheral edge of the through holes; Two feeding coaxial lines, which sequentially include an inner conductor, an insulating layer, and an outer conductor from the inside to the outside, the outer conductor is connected to the metal carrier, and the inner conductor is connected to the metal pad.

2. The low cross-polarization wideband conformal microstrip antenna according to claim 1, characterized in that, The upper surface of the metal carrier forms a first arc surface, the upper surface of the foam layer forms a second arc surface, and the radius of the first arc surface is greater than the radius of the second arc surface.

3. The low cross-polarization wideband conformal microstrip antenna according to claim 2, characterized in that, The gap is annular.

4. The low cross-polarization wideband conformal microstrip antenna according to claim 3, characterized in that, The feeding coaxial lines are differentially fed.

5. The low cross-polarization wideband conformal microstrip antenna according to claim 1, characterized in that The foam layer is made of PMI material.

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