A reflectionless filtering circularly polarized antenna based on asymmetric feed network

Abstract

This invention discloses a reflection-free filtered circularly polarized antenna based on an asymmetric feed network, comprising: a power divider section, an asymmetric feed section, and a radiator section; the terminal open-circuit coupled feed line and the terminal short-circuit coupled feed line are orthogonally placed in planar space; simultaneously, the asymmetric feed section generates the broadband 90° phase difference required for circularly polarized radiation. Furthermore, the out-of-band reflected signals of the asymmetric feed section can generate a broadband 180° phase difference between the two paths, and these reflected signals are effectively dissipated by the isolation resistor loaded on the power divider section, thereby achieving broadband reflection-free performance. Subsequently, a triangular element topology is constructed using a stacked patch configuration to achieve good filtering performance. The reflection-free filtered circularly polarized antenna of this invention has a simple structure and advantages such as broadband reflection-free bandwidth and excellent filtering characteristics.

Description

Technical Field

[0001] This invention belongs to the field of microwave communication technology, specifically a non-reflective filtered circularly polarized antenna based on an asymmetric feeding network. Background Technology

[0002] Circularly polarized antennas are key components in current radar and satellite communication systems due to their ability to effectively reduce multipath loss and their insensitivity to device positioning. With increasing demands on the performance of circularly polarized antennas, integrated design methods have gained widespread attention from researchers. These methods integrate the functions of the antenna and filter to reduce the footprint of the wireless front end and improve efficiency. However, the stopband signal of traditional circularly polarized filter antennas is reflected back to the port, leading to a decrease in the stability of active devices terminated at the port (such as amplifiers and mixers). To address this issue, an effective solution is to design a filter circularly polarized antenna with anti-reflection capabilities, i.e., maintaining frequency selectivity and radiating / receiving circularly polarized wave performance while effectively dissipating out-of-band echo signals. Therefore, research on anti-reflection filter antennas is increasing, but current literature mainly focuses on linearly polarized antennas, with relatively few reports on anti-reflection circularly polarized antennas. In conclusion, anti-reflection filter circularly polarized antennas have significant research value.

[0003] In reference 1 (Paul V and Dhwaj K. A reflectionless circularly polarized high-gain microstrip filtering antenna with wideband response[J].IEEE Transactions on Antennas and Propagation, 2024, 72(6): 5384–5389.), a circularly polarized antenna is achieved by providing two orthogonal signal paths with a 90-degree phase difference using a hybrid ring and employing a dual-point feed method. Simultaneously, the out-of-band reflected signal is dissipated through the isolation resistor of the hybrid ring. However, due to the narrow phase bandwidth of the hybrid ring, the achieved reflection-free bandwidth is also narrow. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by providing a reflection-free filtered circularly polarized antenna based on an asymmetric feeding network. This antenna features a simple design method and excellent reflection-free performance, and can meet the needs of current high-performance wireless communication systems.

[0005] The technical solution to achieve the purpose of this invention is: a reflection-free filtered circularly polarized antenna based on an asymmetric feed network, the antenna comprising: an input port feed section, a power divider section, an asymmetric feed section, a radiator section, and a dielectric substrate;

[0006] The input port feed section is located at the front end of the power divider section; the asymmetric feed section is located above the power divider section and connected to the power divider section through a via; the power divider section is used to provide the asymmetric feed section with a signal of equal amplitude and in phase; the radiator section is located above the asymmetric feed section; the input port feed section, the power divider section, and the asymmetric feed section together form the antenna feed network and feed the radiator section through electromagnetic coupling.

[0007] Furthermore, the power distribution section includes a first transmission line, a second transmission line, a third transmission line, a fourth transmission line, a fifth transmission line, a sixth transmission line, a seventh transmission line, an eighth transmission line, a first isolation resistor, a second isolation resistor, a third isolation resistor, a first via, and a second via;

[0008] The front ends of the first and fifth transmission lines are connected to the power supply portion of the input port; the rear ends of the first transmission line are connected to the front ends of the second transmission line; the rear ends of the second transmission line are connected to the front ends of the third transmission line; the rear ends of the third transmission line are connected to the front ends of the fourth transmission line; the rear ends of the fourth transmission line are connected to the lower end of the first via; the rear ends of the fifth transmission line are connected to the front ends of the sixth transmission line; the rear ends of the sixth transmission line are connected to the front ends of the seventh transmission line; the rear ends of the seventh transmission line are connected to the front ends of the eighth transmission line; the rear ends of the eighth transmission line are connected to the lower end of the second via; the first isolation resistor is connected between the rear ends of the first and fifth transmission lines; the second isolation resistor is connected between the rear ends of the second and sixth transmission lines; and the third isolation resistor is connected between the rear ends of the third and seventh transmission lines.

[0009] Furthermore, the first transmission line and the fifth transmission line have the same characteristic impedance; the second transmission line and the sixth transmission line have the same characteristic impedance; the third transmission line and the seventh transmission line have the same characteristic impedance; and the fourth transmission line and the eighth transmission line have the same characteristic impedance.

[0010] Furthermore, the electrical lengths of the first, second, third, fifth, sixth, and seventh transmission lines are all the same, at 90°, and the electrical lengths of the fourth and eighth transmission lines are the same.

[0011] Furthermore, the asymmetric power supply section includes a terminal short-circuit coupling feeder and a terminal open-circuit coupling feeder, wherein the terminal short-circuit coupling feeder includes a coupling feeder and a short-circuit grounding via.

[0012] The front end of the terminal open-circuit coupling feeder is connected to the upper end of the first via; the front end of the terminal short-circuit coupling feeder is connected to the upper end of the second via; the short-circuit grounding via is placed at the end of the coupling feeder; the terminal open-circuit coupling feeder and the terminal short-circuit coupling feeder are orthogonally placed in planar space.

[0013] Furthermore, the radiator portion includes a first radiator and a second radiator; the first radiator of the radiator portion is disposed directly below the second radiator.

[0014] Furthermore, both the first radiator and the second radiator are rectangular patch antennas.

[0015] Furthermore, the dielectric substrate portion includes a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a first prepreg, a second prepreg, and a metal ground;

[0016] The first dielectric substrate is disposed below the second dielectric substrate, and the two are bonded together by a first prepreg; the second dielectric substrate is disposed below the third dielectric substrate, and the two are bonded together by a second prepreg; the metal ground is disposed above the second dielectric substrate.

[0017] Furthermore, the input port power supply section and the power divider section are disposed below the first dielectric substrate; the asymmetric power supply section is disposed above the second dielectric substrate; the first radiator is disposed below the third dielectric substrate; and the second radiator is disposed above the third dielectric substrate.

[0018] Furthermore, the power divider is a third-order Wilkinson power divider, and has the same center frequency as the radiator section.

[0019] Compared with the prior art, the significant advantages of this invention are:

[0020] (1) The non-reflective filtered circularly polarized antenna based on an asymmetric feed network proposed in this invention uses a pair of orthogonal short-circuited and open-circuited asymmetric feed lines to generate the broadband 90° phase difference required for circularly polarized radiation. At the same time, the out-of-band reflected signals of the asymmetric feed structure can generate a broadband 180° phase difference between the two paths. These signals are effectively dissipated by the isolation resistor loaded on the input power divider, thereby achieving broadband non-reflective performance.

[0021] (2) By using a stacked patch method, a triangular element topology is constructed to achieve good filtering performance.

[0022] (3) The non-reflection filtered circularly polarized antenna of the present invention has a simple structure, does not require additional absorption circuit, and has advantages such as wide non-reflection bandwidth and excellent filtering characteristics.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0024] Figure 1 This is a three-dimensional assembly diagram of a reflection-free filtered circularly polarized antenna based on an asymmetric feed network in one embodiment.

[0025] Figure 2 This is a bottom view of the power distribution section of a reflection-free filtered circularly polarized antenna in one embodiment.

[0026] Figure 3 This is a top view of the asymmetric feed section of a reflection-free filtered circularly polarized antenna in one embodiment.

[0027] Figure 4 This is a graph of the S11 parameters for a non-reflective filtered circularly polarized antenna in one embodiment.

[0028] Figure 5 This is a gain curve of a non-reflective filtered circularly polarized antenna in one embodiment.

[0029] Figure 6 Here is the radiation pattern of a reflection-free filtered circularly polarized antenna in one embodiment, wherein Figure 6 (a) in the diagram is the radiation pattern of the xz plane of the reflection-free filtered circularly polarized antenna. Figure 6 (b) in the diagram is the radiation pattern of the yz plane of the non-reflective filtered circularly polarized antenna. Detailed Implementation

[0030] In the following sections, various embodiments of a reflection-free filtered circularly polarized antenna based on an asymmetric feed network will be described more fully. Various embodiments may be made with respect to this disclosure, and adjustments and changes may be made therein. However, it should be understood that there is no intention to limit the various embodiments of this disclosure to the specific embodiments disclosed herein, but rather this disclosure should be understood to cover all adjustments, equivalents, and / or alternatives falling within the spirit and scope of the various embodiments of this disclosure.

[0031] The terms used in various embodiments of the reflection-free filtered circularly polarized antenna based on an asymmetric feed network (such as "first," "second," etc.) may modify various components in various embodiments, but are not limiting of the corresponding components. For example, the above terms do not limit the order and / or importance of the components. The above terms are used only for the purpose of distinguishing one component from others. For example, "first user facility" and "second user facility" refer to different user facilities, although both are user facilities. For example, without departing from the scope of various embodiments of this disclosure, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component.

[0032] It should be noted that when describing the connection relationship between the power divider section and the asymmetric feed section in a reflection-free filtered circularly polarized antenna, if describing the "connection" of one component to another, the first component can be directly connected to the second component, and a third component can be "connected" between the first and second components. Conversely, when one component is "directly connected" to another component, it can be understood that there is no third component between the first and second components.

[0033] The terminology used in the various embodiments of the reflection-free filtered circularly polarized antenna is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of this disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this disclosure pertain. Terms (such as those defined in generally used dictionaries) are to be interpreted as having the same meaning as in the context of the relevant art and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this disclosure.

[0034] In one embodiment, combined Figures 1 to 3 As shown, the reflection-free filtered circularly polarized antenna based on an asymmetric feed network includes: an input port feed section 1, a power divider section 2, an asymmetric feed section 3, a radiator 4, and a dielectric substrate 5. The dielectric substrate includes a first dielectric substrate 511, a second dielectric substrate 512, a third dielectric substrate 513, a first prepreg 521, a second prepreg 522, and a metal ground 6. The input port feed section 1 and the power divider section 2 are placed on the lower surface of the first dielectric substrate 511. The asymmetric feed section 3 is placed on the upper surface of the second dielectric substrate 512. The metal ground 6 is placed on the lower surface of the second dielectric substrate 512. The first radiator 41 is placed on the lower surface of the third dielectric substrate 513. The second radiator 42 is placed on the upper surface of the third dielectric substrate 513. The first dielectric substrate 511 is placed below the second dielectric substrate 512, and the two are bonded together by the first prepreg 521. The second dielectric substrate 512 is placed below the third dielectric substrate 513, and the two are bonded together by the second prepreg 522.

[0035] Furthermore, in one embodiment, the input port power supply section 1 is disposed at the front end of the power divider section 2; the power divider section 2 includes a first transmission line 211, a second transmission line 212, a third transmission line 213, a fourth transmission line 214, a fifth transmission line 221, a sixth transmission line 222, a seventh transmission line 223, an eighth transmission line 224, a first isolation resistor 231, a second isolation resistor 232, a third isolation resistor 233, a first via 241, and a second via 242;

[0036] In the power distribution section, the front ends of the first transmission line 211 and the fifth transmission line 221 are connected to the input port power supply section; the rear end of the first transmission line 211 is connected to the front end of the second transmission line 212; the rear end of the second transmission line 212 is connected to the front end of the third transmission line 213; the rear end of the third transmission line 213 is connected to the front end of the fourth transmission line 214; the rear end of the fourth transmission line 214 is connected to the lower end of the first via 241; the rear end of the fifth transmission line 221 is connected to the front end of the sixth transmission line 222; the rear end of the sixth transmission line 222 is connected to the front end of the seventh transmission line 223; the rear end of the seventh transmission line 223 is connected to the front end of the eighth transmission line 224; and the rear end of the eighth transmission line 224 is connected to the lower end of the second via 242. The first isolation resistor 231 is connected between the rear ends of the first transmission line 211 and the fifth transmission line 221; the second isolation resistor 232 is connected between the rear ends of the second transmission line 212 and the sixth transmission line 222; and the third isolation resistor 233 is connected between the rear ends of the third transmission line 213 and the seventh transmission line 223.

[0037] Preferably, in some embodiments, in the power distribution section, the first transmission line 211 and the fifth transmission line 221 have the same characteristic impedance; the second transmission line 212 and the sixth transmission line 222 have the same characteristic impedance; the third transmission line 213 and the seventh transmission line 223 have the same characteristic impedance; the fourth transmission line 214 and the eighth transmission line 224 have the same characteristic impedance; the electrical lengths of the first transmission line 211, the second transmission line 212, the third transmission line 213, the fifth transmission line 221, the sixth transmission line 222, and the seventh transmission line 223 are all the same at 90°; and the electrical lengths of the fourth transmission line 214 and the eighth transmission line 224 are all the same.

[0038] It can be seen that in the aforementioned non-reflective filtered circularly polarized antenna, the power divider 2 is a third-order Wilkinson power divider and has the same center frequency as the radiator 4.

[0039] Further, in one embodiment, the asymmetric power supply section includes a terminal open-circuit coupling feeder 31 and a terminal short-circuit coupling feeder 32. The terminal short-circuit coupling feeder 32 includes a coupling feeder 321 and a short-circuit grounding via 322. The front end of the terminal open-circuit coupling feeder 31 is connected to the upper end of the first via 241. The front end of the terminal short-circuit coupling feeder 32 is connected to the upper end of the second via 242. The short-circuit grounding via 322 is placed at the end of the coupling feeder 321. The terminal open-circuit coupling feeder 31 and the terminal short-circuit coupling feeder 32 are orthogonally placed in planar space.

[0040] Furthermore, in one embodiment, the radiator 4 includes a first radiator 41 and a second radiator 42; the first radiator 41 is placed directly below the second radiator 42 in the radiator portion;

[0041] Preferably, in some embodiments, the first radiator 41 and the second radiator 42 are both rectangular patch antennas.

[0042] As a specific example, the invention will be further described and verified in detail in one embodiment.

[0043] Figure 4 The figure shows the S11 parameters of the non-reflective filtered circularly polarized antenna as a function of frequency. It can be found that the antenna center frequency is 3GHz, and the -10dB bandwidth of S11 ranges from 1GHz to 4.64GHz, with a relative bandwidth of 129%. Figure 5 The figure shows the gain curve of the main radiation direction of the non-reflective filtered circularly polarized antenna as a function of frequency. The 3dB bandwidth ranges from 2.85GHz to 3.09GHz, and the maximum gain is 5.85dBi. Figure 6 The image shows the radiation patterns of a reflection-free filtered circularly polarized antenna in the xoz and yoz planes at 3 GHz.

[0044] It should be noted that the non-reflective filter circularly polarized antenna is not limited to operating in the above frequency bands and bandwidths. As needed, the size of the radiator 4 can be adjusted to allow the non-reflective filter circularly polarized antenna to operate in other frequency bands.

[0045] In summary, the reflection-free filtered circularly polarized antenna based on an asymmetric feed network of this invention achieves excellent reflection-free performance and superior frequency selectivity over a wide frequency band with a simple structure, which is beneficial for improving the stability and integration of wireless communication systems. Furthermore, this invention is lightweight, easy to manufacture, and inexpensive.

[0046] It should be understood that when the reflection-free filtered circularly polarized antenna of the present invention is described as being "connected" or "coupled" to another element or layer "on" it, it may be directly connected or coupled to the other element or layer, or there may be intermediate elements or layers. Conversely, when an element is described as being "directly connected" or "directly coupled" to another element or layer "on" it, there are no intermediate elements or layers. Similar numbers in all the figures indicate similar elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0047] Spatially relative terms such as “below,” “under,” “lower,” “above,” “above,” etc., may be used here to describe the relationship between one element or feature and another, as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation other than those shown in the figure. For example, if the device in the figure were flipped over, the element described as “below” or “under” other elements or features would be facing “above” other elements or features. Thus, the exemplary term “below” can include both above and below orientations. Other orientations (rotation 90 degrees or other orientations) may be adopted, and the spatially relative terms used herein will be interpreted accordingly.

[0048] The terms "first," "second," "third," "fourth," etc., used in the specification, claims, and accompanying drawings of this invention, are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0049] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A reflection-free filtered circularly polarized antenna based on an asymmetric feed network, characterized in that, The antenna includes: an input port feed section, a power divider section, an asymmetric feed section, a radiator section, and a dielectric substrate. The input port feed section is located at the front end of the power divider section; the asymmetric feed section is located above the power divider section and connected to the power divider section through a via; the power divider section is used to provide the asymmetric feed section with a signal of equal amplitude and in phase; the radiator section is located above the asymmetric feed section; the input port feed section, the power divider section, and the asymmetric feed section together form the antenna feed network and feed the radiator section through electromagnetic coupling; The asymmetric power supply section includes a terminal short-circuit coupling feeder and a terminal open-circuit coupling feeder. The terminal short-circuit coupling feeder includes a coupling feeder and a short-circuit grounding through hole. The front end of the terminal open-circuit coupling feed line is connected to the upper end of the first via; the front end of the terminal short-circuit coupling feed line is connected to the upper end of the second via; the short-circuit grounding via is placed at the end of the coupling feed line; the terminal open-circuit coupling feed line and the terminal short-circuit coupling feed line are orthogonally placed in planar space. The radiator portion includes a first radiator and a second radiator; The dielectric substrate portion includes a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a first prepreg, a second prepreg, and a metal ground; The first dielectric substrate is disposed below the second dielectric substrate, and the two are bonded together by a first prepreg; the second dielectric substrate is disposed below the third dielectric substrate, and the two are bonded together by a second prepreg; the metal ground is disposed above the second dielectric substrate; The asymmetric power supply portion is disposed above the second dielectric substrate.

2. The reflection-free filtered circularly polarized antenna based on an asymmetric feed network according to claim 1, characterized in that, The power distribution section includes a first transmission line, a second transmission line, a third transmission line, a fourth transmission line, a fifth transmission line, a sixth transmission line, a seventh transmission line, an eighth transmission line, a first isolation resistor, a second isolation resistor, a third isolation resistor, a first via, and a second via; The front ends of the first and fifth transmission lines are connected to the power supply portion of the input port; the rear ends of the first transmission line are connected to the front ends of the second transmission line; the rear ends of the second transmission line are connected to the front ends of the third transmission line; the rear ends of the third transmission line are connected to the front ends of the fourth transmission line; the rear ends of the fourth transmission line are connected to the lower end of the first via; the rear ends of the fifth transmission line are connected to the front ends of the sixth transmission line; the rear ends of the sixth transmission line are connected to the front ends of the seventh transmission line; the rear ends of the seventh transmission line are connected to the front ends of the eighth transmission line; the rear ends of the eighth transmission line are connected to the lower end of the second via; the first isolation resistor is connected between the rear ends of the first and fifth transmission lines; the second isolation resistor is connected between the rear ends of the second and sixth transmission lines; and the third isolation resistor is connected between the rear ends of the third and seventh transmission lines.

3. The reflection-free filtered circularly polarized antenna based on an asymmetric feed network according to claim 2, characterized in that, The first transmission line and the fifth transmission line have the same characteristic impedance; the second transmission line and the sixth transmission line have the same characteristic impedance; the third transmission line and the seventh transmission line have the same characteristic impedance; and the fourth transmission line and the eighth transmission line have the same characteristic impedance.

4. The reflection-free filtered circularly polarized antenna based on an asymmetric feed network according to claim 3, characterized in that, The electrical lengths of the first, second, third, fifth, sixth, and seventh transmission lines are all the same, at 90°, and the electrical lengths of the fourth and eighth transmission lines are the same.

5. The reflection-free filtered circularly polarized antenna based on an asymmetric feed network according to claim 1, characterized in that, The first radiator of the radiator portion is positioned directly below the second radiator.

6. The reflection-free filtered circularly polarized antenna based on an asymmetric feed network according to claim 1, characterized in that, Both the first radiator and the second radiator are rectangular patch antennas.

7. The reflection-free filtered circularly polarized antenna based on an asymmetric feed network according to claim 1, characterized in that, The input port power supply section and power divider section are disposed below the first dielectric substrate; the first radiator is disposed below the third dielectric substrate; and the second radiator is disposed above the third dielectric substrate.

8. The reflection-free filtered circularly polarized antenna based on an asymmetric feed network according to claim 1, characterized in that, The power divider section is a third-order Wilkinson power divider, and its center frequency is the same as that of the radiator section.

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