An ultra-wideband circularly polarized patch antenna

Abstract

The present application belongs to the field of antenna technology and relates to an ultra-wideband circularly polarized patch antenna, comprising: a dielectric substrate and a radiating patch provided on the dielectric substrate; the radiating patch comprises: a feeding branch, a coupling branch, and a grounding branch of an annular structure; the feeding branch comprises: a first portion of a rectangular strip structure, a second portion of a rectangular strip structure, and a third portion of a "U"-shaped structure; one end of the first portion is connected to the inner ring of the grounding branch, and the other end is connected to the middle of the third portion; the second portion is connected to the middle of the first portion so that the second portion and the first portion form a "T"-shaped structure; the open end of the third portion faces the coupling branch and is spaced apart from the coupling branch so that a coupling current is generated between the feeding branch and the coupling branch; one end of the coupling branch is connected to the inner ring of the grounding branch. The present application can achieve ultra-wideband and circular polarization.

Description

Technical Field

[0001] The present application relates to the field of antenna technology, and in particular to an ultra-wideband circularly polarized patch antenna. Background Art

[0002] With the recent development of satellite navigation systems, the Global Navigation Satellite System (GNSS) has gradually become a core component of various positioning, navigation, and timing applications. As China's independently developed global satellite navigation system, the BeiDou system features high precision, multi-frequency bands, and global coverage, and has been widely used in various industries. With the advancement of technology, the integration of navigation systems has become increasingly common. To ensure that these devices can stably and accurately receive BeiDou satellite signals, antenna technology has become a key component.

[0003] However, many existing antennas only support a single or narrow frequency band and cannot cover all BeiDou system frequency bands, resulting in unstable or lost signal reception. Circularly polarized antennas, on the other hand, are widely used in satellite communication systems because they can effectively reduce interference from multipath effects.

[0004] Based on this, how to realize wide-band circularly polarized antennas has gradually become a research hotspot. Summary of the Invention

[0005] Based on this, it is necessary to provide an ultra-wideband circularly polarized patch antenna to address the above technical problems, which can achieve ultra-wideband and circular polarization.

[0006] An ultra-wideband circularly polarized patch antenna, comprising: a dielectric substrate and a radiation patch provided on the dielectric substrate;

[0007] The radiation patch includes: a feeding branch, a coupling branch and a grounding branch of a ring structure;

[0008] The feeding branch comprises: a first portion with a rectangular strip structure, a second portion with a rectangular strip structure, and a third portion with a "U"-shaped structure; one end of the first portion is connected to the inner ring of the grounding branch, and the other end is connected to the middle portion of the third portion; the second portion is connected to the middle portion of the first portion, so that the second portion and the first portion form a "T"-shaped structure; the open end of the third portion faces the coupling branch and is spaced apart from the coupling branch, so that a coupling current is generated between the feeding branch and the coupling branch;

[0009] One end of the coupling branch is connected to the inner ring of the grounding branch.

[0010] In one embodiment, the coupling branch comprises: a first component of a rectangular strip structure, a second component of an "L"-shaped structure, and a third component of a rectangular strip structure;

[0011] One end of the first component is connected to the inner ring of the grounding branch;

[0012] One end of the second component is connected to one end of the first component and is spaced apart from the grounding branch;

[0013] One end of the third component is connected to the other end of the second component, and the other end of the third component is arranged to cross the other end of the first component;

[0014] The first component, the second component, and the third component enclose a rectangular space.

[0015] In one embodiment, the other end of the third component is bent toward one end of the first component, so that the third component forms a step-shaped structure, and a groove is formed at a corner end of the rectangular space.

[0016] In one embodiment, the second component includes: a first section and a second section;

[0017] One end of the first segment is connected to one end of the second segment;

[0018] The other end of the first section is connected to the first component, and the first section is spaced and arranged parallel to the inner ring of the grounding branch;

[0019] The other end of the second section is arranged at the center of the grounding branch and extends to the middle of the opening of the "U"-shaped structure.

[0020] In one embodiment, the grounding branch comprises: a first member, two second members and a third member;

[0021] The two ends of the first member are respectively connected to one corresponding end of the second member, and the two ends of the third member are respectively connected to the other corresponding end of the second member, so that the grounding branch forms a rectangular ring structure;

[0022] Two symmetrical through slots are provided in the middle of the third component, so as to divide the third component into a first portion, a second portion and a third portion which are arranged at intervals, and the second portion is connected to the feeding branch.

[0023] In one embodiment, the first portion and the third portion are symmetrically arranged on both sides of the second portion, and the width of the first portion is greater than the width of the second portion, so that the third component forms an inverted isosceles trapezoidal groove at the midpoint of the inner ring of the grounding branch.

[0024] In one embodiment, the feeding branch and the coupling branch have the same area.

[0025] In one embodiment, the distance between the feeding branch and the coupling branch is less than 1% of the length of any side of the grounding branch.

[0026] In one embodiment, the ground branch is connected to the outer conductor of the connector, and the first portion of the feeding branch is connected to the inner conductor of the connector to implement coplanar waveguide feeding.

[0027] In one embodiment, the dielectric substrate is made of flexible material to make the antenna wearable.

[0028] The above-mentioned ultra-wideband circularly polarized patch antenna is designed with a feeding branch, a coupling branch and a grounding branch. The current is coupled from the third part of the feeding branch to the coupling branch, and after passing through the first component, the second component and the third component of the coupling branch, it finally flows to the outer floor branch and completes the radiation, forming a complete circular current path, thereby realizing the normal operation of the antenna. The antenna has an ultra-wide operating frequency band, an ultra-wide axial ratio bandwidth and an ultra-wide circular polarization performance, which can cover multiple Beidou frequency bands, thereby enhancing its compatibility and stability with satellite signals, and can adapt to different bending shapes of the human body, maintain high signal reception performance in a variety of postures, have a low specific absorption rate and good wearing comfort, and meet the application requirements of the Beidou satellite navigation system in the field of wearable devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 1 is a schematic structural diagram of an ultra-wideband circularly polarized patch antenna according to an embodiment;

[0030] Figure 2 Schematic diagram of the structure of an antenna feeding branch in one embodiment;

[0031] Figure 3 Schematic diagram of the structure of an antenna coupling branch in one embodiment;

[0032] Figure 4 A schematic diagram of the structure of an antenna grounding branch in one embodiment;

[0033] Figure 5 is a dimensional diagram of an antenna in one embodiment;

[0034] Figure 6 is a front view of an antenna in one embodiment;

[0035] Figure 7 is a side view of an antenna in one embodiment;

[0036] Figure 8 A diagram of a darkroom environment where an antenna is located in one embodiment;

[0037] Figure 91. A comparison diagram of the simulation and measured results of the S11 and axial ratio of the antenna in one embodiment;

[0038] Figure 10 1. A diagram comparing the simulated and measured directional patterns of an antenna at 1575.45 MHz in one embodiment;

[0039] Figure 11 1. A diagram showing a comparison of simulation and measurement results of the antenna radiation pattern at 1176.45 MHz in one embodiment;

[0040] Figure 12 1. A comparison diagram of the simulated and measured directional patterns of an antenna at 1268.52 MHz in one embodiment;

[0041] Figure 13 is a wearable schematic diagram of an antenna in one embodiment;

[0042] Figure 14 This is a diagram showing the S11 measured result when the antenna is attached to the left shoulder of a human body in one embodiment;

[0043] Figure 15 Schematic diagram of SAR distribution simulation of the BeiDou System (BDS) antenna of one embodiment when worn on the right shoulder at frequencies B1 (1575.42 MHz), B2 (1176.45 MHz), and B3 (1268.52 MHz).

[0044] Reference numerals:

[0045] Feed branch 1;

[0046] Part 1: 11; Part 2: 12; Part 3: 13, Article 1: 131, Article 2: 132, Article 3: 133;

[0047] Coupling branch 2;

[0048] First component 21; second component 22, first section 221, second section 222; third component 23;

[0049] Ground branch 3;

[0050] The first component 31 ; the second component 32 ; the third component 33 , the first portion 331 , the second portion 332 , and the third portion 333 . DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in this application without creative work are within the scope of protection of this application.

[0052] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0053] In addition, the terms "first," "second," and so on, used in this application are for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "multiple groups" means at least two groups, such as two groups, three groups, and so on, unless otherwise specifically defined.

[0054] In this application, unless otherwise specified or limited, the terms "connect," "fix," etc. should be understood in a broad sense. For example, "fix" can mean a fixed connection, a detachable connection, or an integral connection; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean internal communication between two elements or an interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0055] In addition, the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0056] The present application provides an ultra-wideband circularly polarized patch antenna, such as Figures 1 to 4 As shown, in one embodiment, it includes: a dielectric substrate and a radiation patch.

[0057] The dielectric substrate is a plate-like structure that provides support for the radiation patch.

[0058] Preferably, the dielectric substrate uses a flexible material so that the antenna can bend and fit the human body surface, forming a flexible wearable antenna to meet the needs of wearable devices. Compared with traditional antennas using hard materials or rigid structures in the existing technology, flexible wearable antennas can adapt to the natural curves and movement characteristics of the human body and are suitable for long-term wear without affecting the performance of the antenna itself.

[0059] The radiation patch is arranged on a dielectric substrate and comprises a feeding branch, a coupling branch and a grounding branch.

[0060] The feed branch is located inside the ground branch and connected to the inner ring of the ground branch. The feed branch consists of a first part, a second part, and a third part. The first part is a rectangular strip structure, one end of which is connected to the inner ring of the ground branch and the other end is connected to the middle of the third part to achieve impedance matching and optimize circular polarization performance. The second part is a rectangular strip structure, connected to the middle of the first part, so that the second part and the first part form a "T" shape as a whole, which achieves impedance matching and optimizes broadband characteristics. The third part is a "U"-shaped structure, with its open end facing the coupling branch and spaced apart from the coupling branch to generate coupling current between the feed branch and the coupling branch.

[0061] The coupling branch is arranged inside the grounding branch and is connected to the inner ring of the grounding branch.

[0062] The grounding branch has a ring structure.

[0063] Preferably, the areas of the feeding branch and the coupling branch are equal to each other, so as to improve the axial ratio bandwidth.

[0064] Further preferably, the distance between the feeding branch and the coupling branch is less than 1% of the length of any side of the grounding branch, so as to improve the coupling effect between the feeding branch and the coupling branch, and improve the impedance matching effect between the feeding branch and the antenna, thereby further improving the bandwidth and achieving a wider ultra-wideband.

[0065] Further preferably, the third part includes: a first strip, a second strip and a third strip, and the first strip, the second strip and the third strip are all rectangular structures; one end of the first strip is vertically connected to one end of the third strip, and the other end extends toward the coupling branch; one end of the second strip is vertically connected to the other end of the third strip, and the other end extends toward the coupling branch; one end of the third strip is connected to the first strip, and the other end is connected to the second strip; the distance between the first strip and the coupling branch is smaller than the distance between the second strip and the coupling branch, and the length and width of the first strip are both smaller than the second strip, so as to improve the coupling effect between the feeding branch and the coupling branch, make the coupling strength between the first strip and the second strip and the coupling branch consistent, and form a 90° phase difference, thereby achieving better circular polarization performance.

[0066] More preferably, the ground branch serves as a ground plane, the ground branch is connected to the outer conductor of a connector (eg, an SMA connector), and the first portion of the feeding branch is connected to the inner conductor of the connector to implement coplanar waveguide (CPW) feeding and miniaturization.

[0067] In another embodiment, the coupling branch includes: a first component, a second component, and a third component; the first component, the second component, and the third component are uniform strip structures of equal width and enclose a rectangular space.

[0068] The first component is a rectangular strip structure, one end of which is connected to the inner ring of the grounding branch, and the other end of which extends toward the inside of the grounding branch.

[0069] The second component is an "L"-shaped strip structure, one end of which is connected to one end of the first component and is spaced apart from the grounding branch, and the other end is connected to the third component.

[0070] The third component is a rectangular strip structure, one end of which is connected to the other end of the second component, and the other end of which is arranged to cross the other end of the first component.

[0071] Preferably, the other end of the third component is bent toward one end of the first component so that the third component forms a stepped structure, and a groove is formed at one corner end of the rectangular space to reduce the axial ratio and improve the circular polarization performance.

[0072] Further preferably, the second component includes a first section and a second section. One end of the first section is connected to one end of the second section; the other end of the first section is connected to the first component, and the first section is spaced and arranged parallel to the inner ring of the grounding branch; the other end of the second section is located at the center of the grounding branch and extends to the middle of the opening of the "U"-shaped structure to improve impedance matching.

[0073] In another embodiment, the grounding branch includes: a first component, two second components and a third component; the first component, a second component, the third component and another second component are connected end to end so that the grounding branch forms a rectangular ring structure.

[0074] The first component is a rectangular structure, and its two ends are respectively connected to a corresponding end of the second component.

[0075] The second component is a rectangular structure, one corresponding end of which is connected to both ends of the first component, and the other corresponding end of which is connected to both ends of the third component.

[0076] The third component is a rectangular structure, with its two ends connected to the other corresponding ends of the second component respectively, and two symmetrical through grooves are provided in the middle to divide the third component into a first part, a second part and a third part which are arranged at intervals, wherein the second part is connected to the feeding branch.

[0077] Preferably, the first part and the third part are symmetrically arranged on both sides of the second part, and the width of the first part is greater than the width of the second part, so that the third component forms an inverted isosceles trapezoidal groove at the midpoint of the inner ring of the grounding branch to achieve better impedance matching and reduce the S11 of the antenna.

[0078] Further preferably, the coupling branch is connected to the second component of the grounding branch to form a biased structure, which is conducive to achieving right-hand circular polarization.

[0079] More preferably, the first member, the second member, the first portion of the third member, and the second portion of the third member have different widths to achieve better circular polarization and a wider axial ratio bandwidth.

[0080] The above-mentioned ultra-wideband circularly polarized patch antenna is designed with a feeding branch, a coupling branch and a grounding branch. The current is coupled from the third part of the feeding branch to the coupling branch, and after passing through the first component, the second component and the third component of the coupling branch, it finally flows to the outer floor branch and completes the radiation, forming a complete circular current path, thereby realizing the normal operation of the antenna. The antenna has an ultra-wide operating frequency band, an ultra-wide axial ratio bandwidth and an ultra-wide circular polarization performance, which can cover multiple Beidou frequency bands, thereby enhancing its compatibility and stability with satellite signals, and can adapt to different bending shapes of the human body, maintain high signal reception performance in a variety of postures, have a low specific absorption rate and good wearing comfort, and meet the application requirements of the Beidou satellite navigation system in the field of wearable devices.

[0081] In a specific embodiment, the dielectric substrate is made of polyimide (PI) material with a dielectric constant of 3.5 and a thickness of 0.2 mm. The radiating patch is made of copper foil and mounted on the dielectric substrate. The overall dimensions of the antenna are 77.9 mm × 73.2 mm × 0.2 mm.

[0082] like Figure 5 The specific dimensions are as follows:

[0083] W=73.9mm, L=77.2mm, W1=7mm, W2=4mm, W3=2mm, W4=5mm, W5=4mm, W6=3mm, W7=3mm, L1=9mm, L2=7mm, L3=11mm, L4=11.7mm, L5=10.6mm, L6=12mm, L7=24mm , L8=15mm, L9=17.1mm, L10=13.3mm, L11=19mm, L12=14.3mm, L13=18.5mm, L14=6.5mm, L15=55.2mm, L16=7mm, L17=5.9mm, S=33mm, g=0.2mm, g1=0.6mm.

[0084] like Figures 6 and 7 As shown, the antenna is physically manufactured based on standard PCB manufacturing, soldering and assembly procedures.

[0085] like Figure 8 The anechoic chamber environment shown above uses the 3D electromagnetic simulation software CST Studio Suite to simulate and test the above antenna.

[0086] like Figure 9 The comparison of the antenna's S11 and axial ratio between simulation and measurement shows that the measured S11 curve is below -10dB in the 1100MHz-2300MHz frequency band. The general trend of the measured S11 curve is consistent with the simulation results, and the measured S11 is superior to the simulation results in the 1400MHz-2300MHz frequency band. Furthermore, the measured axial ratio curve is essentially consistent with the simulated one, and the measured 3dB axial ratio operating bandwidth is approximately 1100MHz-1700MHz.

[0087] like Figures 10 to 12 The comparison results of the simulation and measurement of the antenna's radiation pattern at different frequencies (the actual object is in an unbent state) are shown in the figure. It can be seen that the measured RHCP radiation pattern curve is basically the same as the simulated RHCP radiation pattern curve. Figure 1 However, the measured RHCP gain is slightly smaller than the simulated RHCP gain, which is more obvious in the directional pattern result at 1575.45MHz. At this time, the measured RHCP gain is about 1dB lower than the simulated RHCP gain. This is due to the precision error in manufacturing and the error caused by testing (including the errors in reading the directional pattern test data and the secondary calculation of the gain).

[0088] like Figure 13 Wearable schematic of the antenna shown, with the antenna attached to the right shoulder of a human body.

[0089] like Figure 14 The S11 measurement results for the antenna attached to the left shoulder are shown. In the 1150-2170MHz range, the S11 curve remains below -10dB, effectively covering all major navigation frequency bands. This demonstrates that bending the antenna and attaching it to the body does not affect its excellent performance.

[0090] like Figure 15Figure 4 shows a schematic diagram of the SAR distribution simulation of the Beidou system (BDS) with the antenna shown, worn on the right shoulder at frequencies B1 (1575.42 MHz), B2 (1176.45 MHz), and B3 (1268.52 MHz) (average mass 1.0 g). SAR is the simulated specific absorption rate of radiation, which refers to the energy absorbed per unit mass of human tissue and is an important factor for wearable antennas. The maximum SAR values ​​for the B1, B2, and B3 antennas are 0.801 W / kg, 0.477 W / kg, and 0.555 W / kg, respectively. All SAR values ​​are within the internationally prescribed human safety limit of 1.6 W / kg, meeting international standards and demonstrating power safety.

[0091] In summary, the operating bandwidth of the antenna of the present application is 1100-2300 MHz, the relative impedance bandwidth is 70.6%, the axial ratio (AR) bandwidth is 1100-1700 MHz, and the axial ratio relative bandwidth is 42.9%. It has an ultra-wide operating frequency band and axial ratio bandwidth, and is lightweight and portable. It can adapt to different bending shapes of the human body and maintain good radiation characteristics under various bending conditions. It has broad application prospects in the Beidou satellite navigation system and wearable devices.

[0092] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0093] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An ultra-wideband circularly polarized patch antenna, characterized in that: include: A dielectric substrate and a radiation patch provided on the dielectric substrate; The radiation patch includes: a feeding branch, a coupling branch and a grounding branch of a ring structure; The feeding branch comprises: a first portion with a rectangular strip structure, a second portion with a rectangular strip structure, and a third portion with a "U"-shaped structure; one end of the first portion is connected to the inner ring of the grounding branch, and the other end is connected to the middle portion of the third portion; the second portion is connected to the middle portion of the first portion, so that the second portion and the first portion form a "T"-shaped structure; the open end of the third portion faces the coupling branch and is spaced apart from the coupling branch, so that a coupling current is generated between the feeding branch and the coupling branch; One end of the coupling branch is connected to the inner ring of the grounding branch; The coupling branch includes: a first component of a rectangular strip structure, a second component of an "L"-shaped structure, and a third component of a rectangular strip structure; One end of the first component is connected to the inner ring of the grounding branch; One end of the second component is connected to one end of the first component and is spaced apart from the grounding branch; One end of the third component is connected to the other end of the second component, and the other end of the third component is arranged to cross the other end of the first component; The first component, the second component, and the third component enclose a rectangular space.

2. The ultra-wideband circularly polarized patch antenna according to claim 1, wherein: The other end of the third component is bent toward one end of the first component, so that the third component forms a step-shaped structure and a groove is formed at one corner end of the rectangular space.

3. The ultra-wideband circularly polarized patch antenna according to claim 2, wherein: The second component includes: a first section and a second section; One end of the first segment is connected to one end of the second segment; The other end of the first section is connected to the first component, and the first section is spaced and arranged parallel to the inner ring of the grounding branch; The other end of the second section is located at the center of the grounding branch and extends to the middle of the opening of the "U"-shaped structure.

4. The ultra-wideband circularly polarized patch antenna according to any one of claims 1 to 3, characterized in that: The grounding branch comprises: a first component, two second components and a third component; The two ends of the first member are respectively connected to one corresponding end of the second member, and the two ends of the third member are respectively connected to the other corresponding end of the second member, so that the grounding branch forms a rectangular ring structure; Two symmetrical through slots are provided in the middle of the third component, so as to divide the third component into a first portion, a second portion and a third portion which are arranged at intervals, and the second portion is connected to the feeding branch.

5. The ultra-wideband circularly polarized patch antenna according to claim 4, characterized in that: The first portion and the third portion are symmetrically arranged on both sides of the second portion, and the width of the first portion is greater than that of the second portion, so that the third component forms an inverted isosceles trapezoidal groove at the midpoint of the inner ring of the grounding branch.

6. The ultra-wideband circularly polarized patch antenna according to any one of claims 1 to 3, characterized in that: The feeding branch and the coupling branch have the same area.

7. The ultra-wideband circularly polarized patch antenna according to any one of claims 1 to 3, characterized in that: The distance between the feeding branch and the coupling branch is less than 1% of the length of any side of the grounding branch.

8. The ultra-wideband circularly polarized patch antenna according to any one of claims 1 to 3, characterized in that: The grounding branch is connected to the outer conductor of the connector, and the first part of the feeding branch is connected to the inner conductor of the connector to realize coplanar waveguide feeding.

9. The ultra-wideband circularly polarized patch antenna according to any one of claims 1 to 3, characterized in that: The dielectric substrate is made of flexible material to make the antenna wearable.

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