Circularly polarized filtering transmitting array antenna with linear polarized feed

Abstract

The application belongs to the field of electromagnetic field and microwave technology, and discloses a circularly polarized filtering transmission array antenna adopting linear polarization feed, which comprises a feed antenna for radiating linearly polarized electromagnetic waves; a transmission array adopting an antenna-filter-antenna technology frequency selective surface (AFAFSS) unit; and a periodic unit of the antenna-filter-antenna frequency selective surface (AFAFSS) sequentially comprises a rectangular filtering patch antenna as a linear polarization receiving antenna, two cascaded substrate integrated waveguide (SIW) resonant cavities as filters and a wideband circularly polarized antenna as a circular polarization transmitting antenna from a bottom end to a top end in a hierarchical metal structure. The antenna integrates the functions of filters, linear polarization-circular polarization wave conversion and high-gain radiators, and through rotating the transmitting antennas of hundreds of AFAFSS units, appropriate phase compensation can be realized to form a high-gain CP radiation beam, and meanwhile, the AFAFSS has the functions of filtering and linear polarization-circular polarization wave conversion.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic field and microwave technology, specifically relating to a circularly polarized filtered transmission array antenna using a linearly polarized feed source. Background Technology

[0002] Transmitted array antennas possess advantages such as high gain, planar design, and low cost, and their concept has garnered widespread attention from industry and academia since its inception. Furthermore, compared to linearly polarized (LP) waves, circularly polarized (CP) waves are more effective in reducing polarization mismatch effects and combating multipath interference. Therefore, circularly polarized (CP) antennas are widely used in various microwave systems, such as satellite communications, global navigation systems, and remote sensing. Circularly Polarized Filtering Transmitted Array Antennas (CPFTA) are antennas with filtering characteristics proposed based on transmitted array antennas. Compared to traditional transmitted array antennas, CPFTAs can simultaneously achieve high-efficiency radiation and suppression of unwanted signals through the filtering antenna. CPFTAs can use a circularly polarized antenna as their feed antenna and a circularly polarized sensitive frequency selective surface as their transmission array. However, circularly polarized feed antennas typically suffer from drawbacks such as complex structure and cumbersome implementation. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a circularly polarized filtered transmission array antenna employing a linearly polarized feed source, thereby solving the problems of complex structure and cumbersome implementation of circularly polarized feed source antennas in the prior art.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A circularly polarized filtered transmission array antenna employing a linearly polarized feed source includes:

[0006] Feed antenna, used to radiate linearly polarized electromagnetic waves;

[0007] The transmission array employs frequency selective surface (AFA FSS) elements of antenna-filter-antenna technology. The periodic elements of the antenna-filter-antenna frequency selective surface (AFA FSS) are a hierarchical metal structure consisting of a rectangular filter patch antenna as a linearly polarized receiving antenna, two cascaded substrate integrated waveguide (SIW) resonant cavities as filters, and a broadband circularly polarized antenna as a circularly polarized transmitting antenna, from bottom to top.

[0008] Furthermore, the feed antenna employs a linearly polarized rectangular waveguide horn antenna to achieve linearly polarized electromagnetic wave radiation.

[0009] Furthermore, the circularly polarized transmitting antenna is disposed on the first dielectric substrate, the linearly polarized receiving antenna is disposed on the second dielectric substrate, and two cascaded substrate integrated waveguide (SIW) resonant cavity filters are located between the first dielectric substrate and the second dielectric substrate.

[0010] Furthermore, the lower surface of the first dielectric substrate is bonded to the upper surfaces of the two intermediate cascaded substrate integrated waveguide (SIW) resonator filters through a first adhesive layer, and the upper surface of the second dielectric substrate is bonded to the lower surfaces of the two intermediate cascaded substrate integrated waveguide (SIW) resonator filters through a second adhesive layer.

[0011] Furthermore, a symmetrical U-shaped slot is etched on the linear receiving antenna, and an asymmetrical U-shaped slot is etched on the circular transmitting antenna.

[0012] Furthermore, hollow metal tubes are provided on the linear cascaded receiving antenna and the circular cascaded transmitting antenna, and through holes are provided on the two cascaded substrate integrated waveguide (SIW) resonant cavity filters; the two hollow metal tubes are connected to the through holes on the two cascaded substrate integrated waveguide (SIW) resonant cavity filters.

[0013] Furthermore, rectangular slots are provided on one side of the through-hole on the two cascaded substrate integrated waveguide (SIW) resonant cavity filters, and the two cascaded substrate integrated waveguide (SIW) resonant cavity filters are cascaded through the rectangular slots.

[0014] Furthermore, phase compensation is achieved by rotating the circular transmitting antenna.

[0015] Furthermore, the first adhesive layer and the second adhesive layer are made of prepreg.

[0016] Furthermore, the antenna-filter-antenna frequency selective surface (AFAFSS) unit is an aperture-coupled structure in which the energy received by the bottom linearly polarized receiving antenna is coupled to the top circularly polarized transmitting antenna through the aperture.

[0017] The beneficial effects of this invention are:

[0018] 1. This invention is based on the transmission array antenna technology, and uses the antenna-filter-antenna frequency selective surface (AFA FSS) as its transmission array. This transmission array has electromagnetic control functions such as spatial filter, linear polarization-circular polarization wave converter and phase compensator.

[0019] 2. The antenna has characteristics such as high gain and narrow beam, and can achieve circularly polarized wave radiation within the passband of the antenna-filter-antenna frequency selective surface (AFA FSS).

[0020] 3. Phase compensation can be achieved by appropriately rotating the transmitting antenna of the hundreds of antenna-filter-antenna frequency selective surfaces (AFAFSS), thus forming a high-gain circularly polarized radiation beam. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The schematic diagram of the proposed linearly polarized feed-based circularly polarized filter transmission array antenna is shown below.

[0023] Figure 2 Diagram of the antenna-filter-antenna frequency selective surface (AFAFSS) structure;

[0024] Figure 3 Linear plot of transmission and reflection coefficients of the antenna-filter-antenna frequency selective surface (AFAFSS) under normal incident TE polarization;

[0025] Figure 4 Linear plot of axial ratio of circularly polarized transmitted waves on the antenna-filter-antenna frequency selective surface (AFAFSS) under normal incident TE polarization;

[0026] Figure 5 The normalized antenna pattern of the circularly polarized filtered transmission array antenna at a frequency of 30 GHz.

[0027] Figure 6 This is a linear graph showing the gain and axial ratio of a circularly polarized filtered transmission array antenna. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0030] like Figure 1-2 As shown, a circularly polarized filter transmission array antenna employing a linearly polarized feed source includes: a feed antenna and a transmission array; the feed antenna adopts the form of a linearly polarized rectangular waveguide horn antenna for radiating linearly polarized electromagnetic waves; the transmission array adopts a unit form based on antenna-filter-antenna technology with a frequency selective surface (AFAFSS); the periodic unit of the antenna-filter-antenna frequency selective surface (AFAFSS) consists of a rectangular filter patch antenna as a linearly polarized receiving antenna, two cascaded substrate integrated waveguide (SIW) resonant cavities as filters, and a broadband circularly polarized antenna as a circularly polarized transmitting antenna, forming a hierarchical metal structure from bottom to top. This integrates electromagnetic wave control functions such as phase compensation, filtering, and linear-to-circular polarization wave converter.

[0031] The operation of a circularly polarized filtered transmission array antenna can be described as follows: a feed antenna radiates linearly polarized electromagnetic waves, which are received by the linearly polarized receiving antenna on the antenna-filter-antenna frequency selective surface (AFAFSS). These waves then pass through two cascaded substrate integrated waveguide (SIW) resonator filters and are finally emitted by the circularly polarized transmitting antenna on the AFAFSS. Phase compensation and polarization conversion can be achieved by rotating the transmitting antenna on the AFAFSS, thereby forming a high-gain circularly polarized radiation beam.

[0032] This invention is based on transmission array antenna technology, using an antenna-filter-antenna frequency selective surface (AFAFSS) as its transmission array. This transmission array simultaneously has electromagnetic control functions such as a spatial filter, a linear-to-circular polarization wave converter, and a phase compensator.

[0033] The antenna features high gain and narrow beam characteristics, and can achieve circularly polarized wave radiation within the passband of the antenna-filter-antenna frequency selective surface (AFA FSS).

[0034] Phase compensation can be achieved by properly rotating the transmitting antenna of the hundreds of antenna-filter-antenna frequency selective surfaces (AFAFSS), thus forming a high-gain circularly polarized radiation beam.

[0035] A frequency selective surface (FSS) is an array structure of two-dimensional or three-dimensional periodic cells. FSSs are widely used as functional devices such as space electromagnetic filters, reflectors, polarization converters, and absorbers. This invention applies a FSS to the transmission array of a circularly polarized transmission array antenna. In this invention, the FSS can simultaneously realize electromagnetic control functions such as a space filter, a phase compensator, and a linear-to-circular polarization converter, thereby achieving a circularly polarized filtered transmission array antenna.

[0036] Phase compensation is achieved by rotating the transmitting antenna of the antenna-filter-antenna frequency selective surface (AFAFSS) by a certain angle according to the antenna's polarization (right-hand circular polarization / left-hand circular polarization) (counterclockwise / clockwise), with the rotation angle equal to the corresponding compensation phase, thereby obtaining a high-gain circularly polarized radiation beam.

[0037] Figure 1 A schematic diagram of the antenna of this invention is provided. The feed antenna radiates a linearly polarized wave, and the polarization is converted and the corresponding phase is compensated by the transmitting antenna of the rotating antenna-filter-antenna frequency selective surface (AFAFSS), thereby converting the linearly polarized incident wave into a high-gain circularly polarized output beam.

[0038] Figure 2 The diagram shows the structure of an antenna-filter-antenna frequency selective surface (AFAFSS); where (a) is a perspective view, (b) is a circularly polarized transmitting antenna, (c) is two cascaded substrate integrated waveguide (SIW) resonant cavity filters, and (d) is a linearly polarized receiving antenna. The periodic unit of the antenna-filter-antenna frequency selective surface (AFAFSS) is a hierarchical metal structure consisting of a rectangular filter patch antenna as a linearly polarized receiving antenna, two cascaded substrate integrated waveguide (SIW) resonant cavities as filters, and a broadband circularly polarized antenna as a transmitting antenna.

[0039] A circularly polarized transmitting antenna is disposed on a first dielectric substrate, and a linearly polarized receiving antenna is disposed on a second dielectric substrate. Two cascaded substrate integrated waveguide (SIW) resonator filters are located between the first and second dielectric substrates. The lower surface of the first dielectric substrate is bonded to the upper surfaces of the two intermediate cascaded substrate integrated waveguide (SIW) resonator filters via a first adhesive layer, and the upper surface of the second dielectric substrate is bonded to the lower surfaces of the two intermediate cascaded substrate integrated waveguide (SIW) resonator filters via a second adhesive layer.

[0040] Both the first and second dielectric substrates are Rogers 5880 (thickness h1, relative permittivity εr = 2.2), and the first and second adhesive layers are prepregs RF25 (thickness h2, relative permittivity εr = 2.5).

[0041] A symmetrical U-shaped slot is etched on the linear receiving antenna, and an asymmetrical U-shaped slot is etched on the circular transmitting antenna.

[0042] Hollow metal tubes are installed on the linear cascaded receiving antenna and the circular cascaded transmitting antenna, and through holes are installed on the two cascaded substrate integrated waveguide (SIW) resonant cavity filters; the two hollow metal tubes are connected to the through holes on the two cascaded substrate integrated waveguide (SIW) resonant cavity filters. This achieves electromagnetic energy coupling.

[0043] Two cascaded substrate integrated waveguide (SIW) resonant cavity filters have rectangular slots on one side of the vias, and the two SIW resonant cavity filters are cascaded through the rectangular slots. This allows for coupling within the passband of the antenna-filter-antenna frequency selective surface (AFAFSS), while simultaneously introducing a transmission null value in the upper stopband of the AFAFSS.

[0044] The Antenna-Filter-Antenna Frequency Selective Surface (AFAFSS) unit is an aperture-coupled structure in which the energy received by the bottom linearly polarized receiving antenna is coupled to the top circularly polarized transmitting antenna layer through the aperture.

[0045] Figure 3 Linear plot of transmission and reflection coefficients of the antenna-filter-antenna frequency selective surface (AFAFSS) under normal incident TE polarization. Figure 4 This is a linear plot of the axial ratio of the circularly polarized transmitted wave from the antenna-filter-antenna frequency selective surface (AFAFSS) under normal incident TE polarization. It can be observed that the center frequency of this frequency selective surface is 30 GHz. Within the frequency range of 25.6–34.8 GHz, the axial ratio (AR) of the circularly polarized wave is less than 3 dB, meaning this frequency selective surface can be considered a linear-to-circular polarization wave converter. Furthermore, there are transmission zeros at both 22 GHz and 36 GHz, indicating that this frequency selective surface possesses excellent filtering characteristics.

[0046] Figure 5 The image shows the normalized antenna radiation pattern of a circularly polarized filtered transmission array antenna at 30 GHz. The transmission array antenna has dimensions of approximately 90 mm × 90 mm, a focal length of 52 mm, and a linearly polarized waveguide horn feed antenna gain of 13 dBi. The figure shows that the radiation performance of the circularly polarized filtered transmission array antenna is relatively stable within its 3 dB gain band. Overall, under the excitation of a linearly polarized feed, this antenna can achieve a narrow-beam circularly polarized radiation beam.

[0047] Figure 6 The figure shows the gain and axial ratio linearity of the circularly polarized filtered transmission array antenna. It can be easily observed that at 30 GHz, the antenna gain along the z-axis reaches 27.7 dBic, with an aperture efficiency of 57.8%. The antenna's 3 dB gain frequency range is 28–31.5 GHz, and very small gain variation can be observed near 30 GHz. Simultaneously, within the antenna's operating bandwidth, the axial ratio (AR) is less than 3 dB.

[0048] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A circularly polarized filtered transmission array antenna employing a linearly polarized feed, characterized in that, include: Feed antenna, used to radiate linearly polarized electromagnetic waves; The transmission array employs frequency selective surface (AFA FSS) elements of antenna-filter-antenna technology. The periodic elements of the antenna-filter-antenna frequency selective surface (AFA FSS) are a hierarchical metal structure consisting of a rectangular filter patch antenna as a linearly polarized receiving antenna, two cascaded substrate integrated waveguide (SIW) resonant cavities as filters, and a broadband circularly polarized antenna as a circularly polarized transmitting antenna, from bottom to top. The linearly polarized receiving antenna and the circularly polarized transmitting antenna are provided with hollow metal tubes, and the two cascaded substrate integrated waveguide (SIW) resonant cavity filters are provided with through holes; the two hollow metal tubes are connected to the through holes on the two cascaded substrate integrated waveguide (SIW) resonant cavity filters. Two cascaded substrate integrated waveguide (SIW) resonant cavity filters have rectangular slots on one side of the vias, and the two cascaded substrate integrated waveguide (SIW) resonant cavity filters are cascaded through the rectangular slots.

2. The circularly polarized filtered transmission array antenna using a linearly polarized feed source according to claim 1, characterized in that, The feed antenna uses a linearly polarized rectangular waveguide horn antenna to achieve linearly polarized electromagnetic wave radiation.

3. The circularly polarized filtered transmission array antenna using a linearly polarized feed source according to claim 1, characterized in that, The circularly polarized transmitting antenna is disposed on the first dielectric substrate, the linearly polarized receiving antenna is disposed on the second dielectric substrate, and two cascaded substrate integrated waveguide (SIW) resonant cavity filters are located between the first dielectric substrate and the second dielectric substrate.

4. A circularly polarized filtered transmission array antenna employing a linearly polarized feed source according to claim 3, characterized in that, The lower surface of the first dielectric substrate is bonded to the upper surface of the two intermediate cascaded substrate integrated waveguide (SIW) resonator filters through a first adhesive layer, and the upper surface of the second dielectric substrate is bonded to the lower surface of the two intermediate cascaded substrate integrated waveguide (SIW) resonator filters through a second adhesive layer.

5. A circularly polarized filtered transmission array antenna employing a linearly polarized feed source according to claim 4, characterized in that, A symmetrical U-shaped slot is etched on the linearly polarized receiving antenna, and an asymmetrical U-shaped slot is etched on the circularly polarized transmitting antenna.

6. A circularly polarized filtered transmission array antenna employing a linearly polarized feed source according to claim 1, characterized in that, Phase compensation is achieved by rotating the circularly polarized transmitting antenna.

7. A circularly polarized filtered transmission array antenna employing a linearly polarized feed source according to claim 4, characterized in that, The first adhesive layer and the second adhesive layer are made of prepreg.

8. A circularly polarized filtered transmission array antenna employing a linearly polarized feed source according to claim 1, characterized in that, The Antenna-Filter-Antenna Frequency Selective Surface (AFA FSS) element is an aperture-coupled structure in which the energy received by the bottom linearly polarized receiving antenna is coupled to the top circularly polarized transmitting antenna through a through-hole.

Images