Non-reflection filtering circularly polarized antenna based on asymmetric feed network

Abstract

The invention discloses a non-reflection filtering circularly polarized antenna based on an asymmetric feed network. The non-reflection filtering circularly polarized antenna comprises a power dividing part, an asymmetric feed part and a radiator part, the terminal open-circuit coupling feeder line and the terminal short-circuit coupling feeder line are orthogonally arranged in a plane space position; meanwhile, the asymmetric feed part generates a broadband 90-degree phase difference required by circular polarization radiation. Meanwhile, out-of-band reflection signals of the asymmetric feed part can generate a broadband 180-degree phase difference between two paths, the reflection signals are effectively dissipated by an isolation resistor loaded on the power dividing part, and therefore the broadband non-reflection performance is achieved. And then, a triangular element topological structure is constructed by adopting a stacked patch form, so that good filtering performance is realized. The non-reflection filtering circularly polarized antenna is simple in structure, and has the advantages of non-reflection bandwidth, excellent filtering characteristic and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of microwave communication, in particular to a reflection-free filtering circularly polarized antenna based on an asymmetric feeding network. Background Art

[0002] Circularly polarized antennas are key components in current radar and satellite communication systems because they can effectively reduce multipath loss and are insensitive to device positioning. With the increasing performance requirements for circularly polarized antennas, integrated design methods have gradually attracted widespread attention from researchers. This method integrates the functions of antennas and filters to reduce the occupied space of wireless front-ends and improve efficiency. However, the stopband signals of traditional circularly polarized filter antennas are reflected back to the port, resulting in a decrease in the stability of active devices (such as amplifiers and mixers) terminated at the port. To solve this problem, an effective solution is to design a filtered circularly polarized antenna with a reflectionless function, that is, to effectively dissipate out-of-band echo signals while maintaining frequency selectivity and radiation / reception of circularly polarized waves. Therefore, the research on reflectionless filter antennas is increasing, but the literature reported so far focuses on linearly polarized antennas, while there are fewer related reflectionless circularly polarized antennas. In summary, reflectionless filter circularly polarized antennas have important 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 realized by a dual-point feeding method based on a hybrid ring to provide two orthogonal signal paths with a phase difference of 90 degrees. At the same time, the out-of-band reflected signal is dissipated by the isolation resistor of the hybrid ring. However, due to the narrow phase bandwidth of the hybrid ring, the achieved reflection-free bandwidth is narrow. Summary of the invention

[0004] The purpose of the present invention is to address the problems existing in the above-mentioned prior art and provide a reflectionless filtered circularly polarized antenna based on an asymmetric feeding network, which has the characteristics of simple design method and excellent reflectionless performance, and can meet the needs of current high-performance wireless communication systems.

[0005] The technical solution to achieve the purpose of the present invention is: a reflectionless filtering circularly polarized antenna based on an asymmetric feeding network, the antenna comprising: an input port feeding part, a power division part, an asymmetric feeding part, a radiator part and a dielectric substrate;

[0006] The input port feeding part is arranged at the front end of the power dividing part; the asymmetric feeding part is arranged above the power dividing part and is connected to the power dividing part through a via; the power dividing part is used to provide equal-amplitude and in-phase signals for the asymmetric feed line part; the radiator part is arranged above the asymmetric feeding part; the input port feeding part, the power dividing part, and the asymmetric feeding part together constitute a feeding network of the antenna, and feed the radiator part through electromagnetic coupling.

[0007] Further, the power division part 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 hole and a second via hole;

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

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

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

[0011] Further, the asymmetric feeding part includes a terminal short-circuit coupling feeder and a terminal open-circuit coupling feeder, and the terminal short-circuit coupling feeder includes a coupling feeder and a short-circuit grounding through-hole;

[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 through-hole is placed at the end of the coupling feeder; the terminal open-circuit coupling feeder and the terminal short-circuit coupling feeder are placed orthogonally in a plane space position.

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

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

[0015] Further, the dielectric substrate part 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 arranged below the second dielectric substrate, and the two are bonded by a first prepreg; the second dielectric substrate is arranged below the third dielectric substrate, and the two are bonded by the second prepreg; the metal ground is arranged above the second dielectric substrate.

[0017] Furthermore, the input port feeding part and the power dividing part are arranged below the first dielectric substrate; the asymmetric feeding part is arranged above the second dielectric substrate; the first radiator is arranged below the third dielectric substrate; and the second radiator is arranged above the third dielectric substrate.

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

[0019] Compared with the prior art, the present invention has the following significant advantages:

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

[0021] (2) By adopting the stacked patch form, a triangular element topology structure is constructed to achieve good filtering performance.

[0022] (3) The reflectionless filtering circularly polarized antenna of the present invention has a simple structure, does not require an additional absorption circuit, and has the advantages of a wideband reflectionless bandwidth and excellent filtering characteristics.

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a three-dimensional assembly diagram of a reflectionless filtering circularly polarized antenna based on an asymmetric feeding network in one embodiment.

[0025] Figure 2 A bottom view of the power splitter portion of a reflectionless filtering circularly polarized antenna in one embodiment.

[0026] Figure 3 FIG. 1 is a top view of an asymmetric feeding portion of a reflectionless filtering circularly polarized antenna in one embodiment.

[0027] Figure 4 FIG. 4 is a graph showing an S11 parameter curve of a reflection-free filtering circularly polarized antenna in an embodiment.

[0028] Figure 5 FIG. 4 is a gain curve diagram of a reflectionless filtering circularly polarized antenna in one embodiment.

[0029] Figure 6 is a directional diagram of a reflectionless filtered circularly polarized antenna in one embodiment, wherein Figure 6 (a) is the radiation pattern of the circularly polarized antenna without reflection filter in the xz plane. Figure 6 (b) in the figure is the radiation pattern of the reflection-free circularly polarized antenna in the yz plane. DETAILED DESCRIPTION

[0030] In the following, various embodiments of the reflectionless filtered circularly polarized antenna based on the asymmetric feed network will be described more fully. There may be various embodiments of the present 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 the present disclosure to the specific embodiments disclosed herein, but the present disclosure should be understood to cover all adjustments, equivalents and / or alternatives that fall within the spirit and scope of the various embodiments of the present disclosure.

[0031] The expressions (such as "first", "second", etc.) used in various embodiments of the reflectionless filtered circularly polarized antenna based on an asymmetric feed network may modify the various constituent elements in the various embodiments, but may not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing one element from other elements. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, without departing from the scope of the various embodiments of the present disclosure, the first element may be referred to as the second element, and similarly, the second element may also be referred to as the first element.

[0032] It should be noted that when describing the connection relationship between the power division part and the asymmetric feeding part in the reflectionless filter circularly polarized antenna, if it is described that one component element is "connected" to another component element, the first component element can be directly connected to the second component element, and the third component element can be "connected" between the first component element and the second component element. On the contrary, when one component element is "directly connected" to another component element, it can be understood that there is no third component element between the first component element and the second component element.

[0033] The terms used in the various embodiments of the reflectionless filtered circularly polarized antenna are only used for the purpose of describing specific embodiments and are not intended to limit the various embodiments of the present disclosure. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by ordinary technicians in the field to which the various embodiments of the present disclosure belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings, unless clearly defined in the various embodiments of the present disclosure.

[0034] In one embodiment, in combination Figures 1 to 3 As shown, the reflectionless filter circularly polarized antenna based on the asymmetric feeding network includes: an input port feeding part 1, a power division part 2, an asymmetric feeding part 3, a radiator part 4, and a dielectric substrate 5; the dielectric substrate part 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 feeding part 1 and the power division part 2 are placed on the lower surface of the first dielectric substrate 511; the asymmetric feeding part 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 radiator 41 is placed on the lower surface of the second dielectric substrate 513; the 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 by the first prepreg 521; the second dielectric substrate 512 is placed below the third dielectric substrate 513, and the two are bonded by the second prepreg 522;

[0035] Further, in one embodiment, the input port feeding part 1 is arranged at the front end of the power division part 2; the power division part 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] The front ends of the first transmission line 211 and the fifth transmission line 221 in the power division part are connected to the input port feeding part; 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; 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; 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, the first transmission line 211 and the fifth transmission line 221 in the power division part 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, which is 90°; 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 above-mentioned reflectionless filtering circularly polarized antenna, the power division part 4 is a third-order Wilkinson power divider and has the same center frequency as the radiator part 4 .

[0039] Furthermore, in one of the embodiments, the asymmetric feeding part includes a terminal open-circuit coupling feeder 31, a terminal short-circuit coupling feeder 32, and the terminal short-circuit coupling feeder 32 includes a coupling feeder 321 and a short-circuit grounding through-hole 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 through-hole 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 placed orthogonally in a plane space position.

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

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

[0042] As a specific example, in one of the embodiments, the present invention is further verified and explained in detail.

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

[0044] It should be noted that the reflectionless filter circularly polarized antenna is not limited to working in the above-mentioned frequency band and bandwidth. As required, the size of the radiator 4 can be adjusted to make the reflectionless filter circularly polarized antenna work in other frequency bands.

[0045] In summary, the reflectionless filter circularly polarized antenna based on the asymmetric feeding network of the present invention can achieve excellent reflectionless performance and excellent frequency selection performance in a wider frequency band based on a simple structure, which is beneficial to improving the stability and integration of the wireless communication system. At the same time, the present invention has the characteristics of light weight, simple processing and low price.

[0046] It should be understood that when a certain element or layer of the reflectionless filtered circularly polarized antenna in the present invention is said to be "on" another element or layer, "connected" or "coupled" to another element or layer, it may be directly on another element or layer, directly connected or coupled to the other element or layer, or there may be intermediate elements or layers. On the contrary, when a certain element is said to be "directly on" another element or layer, "directly connected" or "directly coupled" to another element or layer, there are no intermediate elements or layers. Similar numbers in all figures indicate similar elements. As used herein, the term "and / or" includes any and all combinations of one or more of the relevant listed items.

[0047] Spatially relative terms may be used for ease of description, such as "under," "below," "lower," "above," "above," etc. to describe the relationship of one element or feature to another element or feature as shown in the figure. It should be understood that the spatially relative terms are intended to include different orientations of the device in use or operation other than the orientation shown in the figure. For example, if the device in the figure is turned over, the elements described as "under" or "below" other elements or features will be facing "above" the other elements or features. Thus, the exemplary term "below" can include both the above and below orientations. The device can be made to take other orientations (rotated 90 degrees or other orientations), and the spatially relative terms used here are interpreted accordingly.

[0048] The terms "first", "second", "third", "fourth", etc. in the specification and claims of the present invention and the above-mentioned drawings, if present, are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0049] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A reflectionless filtering circularly polarized antenna based on an asymmetric feeding network, characterized in that: The antenna comprises: an input port feeding part, a power dividing part, an asymmetric feeding part, a radiator part and a dielectric substrate; The input port feeding part is arranged at the front end of the power dividing part; the asymmetric feeding part is arranged above the power dividing part and is connected to the power dividing part through a via; the power dividing part is used to provide equal-amplitude and in-phase signals for the asymmetric feed line part; the radiator part is arranged above the asymmetric feeding part; the input port feeding part, the power dividing part, and the asymmetric feeding part together constitute a feeding network of the antenna, and feed the radiator part through electromagnetic coupling.

2. The reflectionless filtering circularly polarized antenna based on an asymmetric feeding network according to claim 1, characterized in that: The power division part 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 hole and a second via hole; The front ends of the first transmission line and the fifth transmission line are connected to the input port feeding part; the rear end of the first transmission line is connected to the front end of the second transmission line; the rear end of the second transmission line is connected to the front end of the third transmission line; the rear end of the third transmission line is connected to the front end of the fourth transmission line; the rear end of the fourth transmission line is connected to the lower end of the first via; the rear end of the fifth transmission line is connected to the front end of the sixth transmission line; the rear end of the sixth transmission line is connected to the front end of the seventh transmission line; the rear end of the seventh transmission line is connected to the front end of the eighth transmission line; the rear end of the eighth transmission line is connected to the lower end of the second via; the first isolation resistor is connected between the rear ends of the first transmission line and the fifth transmission line; the second isolation resistor is connected between the rear ends of the second transmission line and the sixth transmission line; the third isolation resistor is connected between the rear ends of the third transmission line and the seventh transmission line.

3. The reflectionless filtering circularly polarized antenna based on an asymmetric feeding network according to claim 2, characterized in that: The first transmission line has the same characteristic impedance as the fifth transmission line; the second transmission line has the same characteristic impedance as the sixth transmission line; the third transmission line has the same characteristic impedance as the seventh transmission line; and the fourth transmission line has the same characteristic impedance as the eighth transmission line.

4. The reflectionless filtering circularly polarized antenna based on an asymmetric feeding network according to claim 3, characterized in that: The electrical lengths of the first transmission line, the second transmission line, the third transmission line, the fifth transmission line, the sixth transmission line and the seventh transmission line are all the same, which is 90°. The electrical lengths of the fourth transmission line and the eighth transmission line are the same.

5. The reflectionless filtering circularly polarized antenna based on an asymmetric feeding network according to claim 2, characterized in that: The asymmetric feeding part includes a terminal short-circuit coupling feeder and a terminal open-circuit coupling feeder, and 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 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 through-hole is placed at the end of the coupling feeder; the terminal open-circuit coupling feeder and the terminal short-circuit coupling feeder are placed orthogonally in a plane space position.

6. The reflectionless filtering circularly polarized antenna based on an asymmetric feeding network according to claim 1, characterized in that: The radiator part includes a first radiator and a second radiator; the first radiator of the radiator part is arranged directly below the second radiator.

7. The reflectionless filtering circularly polarized antenna based on an asymmetric feeding network according to claim 1, characterized in that: The first radiator and the second radiator are both rectangular patch antennas.

8. The reflectionless filtering circularly polarized antenna based on an asymmetric feeding network according to claim 1, characterized in that: The dielectric substrate part 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 arranged below the second dielectric substrate, and the two are bonded by a first prepreg; The second dielectric substrate is arranged below the third dielectric substrate, and the two are bonded by the second prepreg; The metal ground is arranged above the second dielectric substrate.

9. The reflectionless filtering circularly polarized antenna based on an asymmetric feeding network according to claim 1, characterized in that: The input port feeding part and the power dividing part are arranged below the first dielectric substrate; the asymmetric feeding part is arranged above the second dielectric substrate; the first radiator is arranged below the third dielectric substrate; and the second radiator is arranged above the third dielectric substrate.

10. The reflectionless filtering circularly polarized antenna based on an asymmetric feeding network according to claim 1, characterized in that: The power division part is a third-order Wilkinson power divider, and has the same center frequency as the radiator part.

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