Multifunctional broadband filtering antenna based on half-mode gap waveguide cavity

Abstract

The invention discloses an in-band full duplex filtering antenna based on a half-mode gap waveguide cavity. The antenna comprises a pin layer (100); the antenna comprises a pin layer (100), a cavity layer (200) and a grounding plate (300), and the cavity layer (200) and the pin layer (100) are separated by an air gap to form an electromagnetic band gap (EBG) structure. The grounding plate (300) is arranged on the lower surface of the pin layer (100); and the side metal plate (400) is connected to the side surface of the cavity layer (200) through the WR32 waveguide (500).

Description

Technical Field

[0001] This invention belongs to the field of wireless mobile communication technology, and in particular relates to a multifunctional broadband filtering antenna based on a half-mode gap waveguide cavity. Background Technology

[0002] With the rapid development of 5G / 6G and millimeter-wave communication, RF front-ends are facing higher requirements for "large bandwidth, high isolation, small size, and easy assembly." Existing technologies, traditional metal waveguide resonant cavities are large and heavy, and suffer from severe electrical contact losses in the millimeter-wave band; coaxial probe feeding suffers high insertion loss in the millimeter-wave band, making assembly difficult; most reported IBDF antennas are cavity-splitting or board-splitting structures, with isolation relying on large decoupling networks, making it difficult to achieve common aperture, same frequency band, and compact design; while half-mode gap waveguide (HMGW) technology provides contactless, low-loss transmission, its application in filter antennas is still in the exploratory stage, with existing solutions having limited bandwidth and lacking flexible functional integration. This invention proposes an in-band full-duplex filter antenna based on a half-mode gap waveguide cavity, achieving functional switching by multiplexing the pin layer and cavity layer structure, significantly reducing cost and improving design flexibility. Summary of the Invention

[0003] Purpose of the Invention: The purpose of this invention is to propose a filter antenna capable of simultaneously achieving co-aperture, co-band, and full-duplex communication in the millimeter-wave band. High isolation is achieved by utilizing orthogonal modes and orthogonal feeding within the same half-mode gap waveguide cavity. Loss is reduced and assembly is simplified through a contactless half-mode structure. Furthermore, a replaceable pin layer design enables rapid switching between broadband, band-stop, and IBD functions without altering the overall dimensions. Ultimately, this achieves the goals of small size, low loss, easy assembly, and low cost, meeting the urgent needs of 5G / 6G and future millimeter-wave systems for highly integrated and reconfigurable RF front-ends.

[0004] Technical Solution: To achieve the above objectives, this invention proposes an in-band full-duplex filtering antenna based on a half-mode gap waveguide cavity, comprising a pin layer (100), a cavity layer (200), and a ground plane (300). The cavity layer (200) and the pin layer (100) are separated by an air gap to form an electromagnetic bandgap (EBG) structure. The ground plane (300) is disposed on the lower surface of the pin layer (100). A side metal plate (400) is connected to the side of the cavity layer (200) through a WR32 waveguide (500).

[0005] Furthermore, the pin layer (100) is composed of periodically arranged metal pins (110) forming an artificial magnetic conductor AMC, thus creating an electromagnetic bandgap EBG structure.

[0006] Furthermore, the cavity layer (200) includes a half-mode gap waveguide TM mode resonant cavity (210), an H-plane rectangular radiating slot (220), and two E-plane rectangular radiating slots (230). The TM mode resonant cavity (210) is located at the horizontal geometric center of the cavity layer. One end of the H-plane rectangular radiating slot (220) is vertically connected to the upper surface of the half-mode gap waveguide TM mode resonant cavity (210), and the other end is connected to the radiating surface of the cavity layer (200). One end of the two E-plane rectangular radiating slots (230) is vertically connected to the upper surface of the half-mode gap waveguide TM mode resonant cavity (210), and the other end is connected to the radiating surface of the cavity layer (200). The two E-plane rectangular radiating slots (230) are symmetrically distributed on both sides of the H-plane rectangular radiating slot (220).

[0007] Furthermore, the rectangular slot in the middle of the ground plane (300) serves as the first channel feed port, and the rectangular slot in the middle of the ground plane (300) corresponds to the opening on the pin layer (100). The first channel feed port is symmetrical about the cavity layer (200) and is used to excite the TM mode resonator (210) of the half-mode gap waveguide vertically upward. 10，3 / 2 model.

[0008] Furthermore, the rectangular slot in the middle of the side metal plate (400) serves as the second channel feed port, which is spatially orthogonal to the first feed port; and the rectangular slot in the middle of the side metal plate (400) is directly connected to the side wall slot of the cavity layer (200); the second feed port is coupled and excited by the WR32 waveguide (500) through the side wall slot of the cavity layer (200) to the TM mode resonator of the half-mode gap waveguide TM mode resonator (210). 20，1 / 2 model.

[0009] Furthermore, the first channel feed port and the second feed port are geometrically positioned at a 90° angle to achieve orthogonal polarization excitation.

[0010] Furthermore, the dimensions of the H-plane rectangular radiation slot (220) are adjustable, allowing for independent adjustment of the resonant slot mode frequency and TE. 10 Mode frequency.

[0011] Furthermore, the assembly configuration of the pin layer (100) and the cavity layer (200) is interchangeable. By adjusting the arrangement of the metal pins (110) in the pin layer, the three functions of broadband, bandstop, or IBDF can be switched.

[0012] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0013] (1) This invention integrates filtering and antenna functions into a single "half-mode gap waveguide cavity" in the millimeter-wave band. It replaces the traditional full-mode metal cavity with a half-mode structure without electrical contact, which reduces the overall volume by more than half, significantly reduces the weight, and completely eliminates metal contact loss in the millimeter-wave band. By sharing the same cavity with the orthogonal TM10,3 / 2 and TM20,1 / 2 modes and being directly fed by the bottom waveguide and the sidewall WR32 waveguide respectively, it achieves common aperture, same frequency band, and full-duplex operation. The measured port isolation is better than 44dB, which is much higher than the existing cavity splitting or decoupling network solutions.

[0014] (2) This invention utilizes interchangeable pin layer patterns to achieve rapid switching between three functions: "broadband-bandstop-IBFD" while maintaining the same external dimensions. The design cycle is shortened from several weeks of mold re-opening to several hours of pin layer replacement, resulting in a significant cost reduction. Standard rectangular waveguide feeding avoids the insertion loss and assembly difficulty of millimeter-wave coaxial probes. Combined with 3D printing and surface metallization processes, the number of parts, processing time, and assembly tolerance requirements are reduced simultaneously, and the overall manufacturing cost is significantly lower than that of traditional CNC aluminum milling or SIW substrate solutions. Finally, the antenna has a measured gain of over 8dBi and a cross-polarization level of less than -18dB within the 26.5–40GHz range. It has a steep filter roll-off and can be seamlessly embedded in 5G / 6G small base stations, backhaul links, and satellite communication terminals, providing a new solution for millimeter-wave high integration and reconfigurable RF front-ends that combines high performance and low cost. Attached Figure Description

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, so as to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art. The advantages and implementation methods of the present invention will become more apparent. The content of the accompanying drawings is only used to illustrate and explain the present invention, but does not constitute any limitation on the present invention. In the accompanying drawings:

[0016] Figure 1 This is a three-dimensional structural diagram of an in-band full-duplex filtering antenna based on a half-mode gap waveguide cavity according to the present invention.

[0017] Figure 2 This is a schematic diagram of the planar dimensions and feed port of an in-band full-duplex filter antenna based on a half-mode gap waveguide cavity according to the present invention.

[0018] Figure 3 This invention presents the simulation and measured results of the reflection coefficient and gain curve of an in-band full-duplex filter antenna based on a half-mode gap waveguide cavity.

[0019] Figure 4 This invention relates to the radiation pattern of an in-band full-duplex filter antenna based on a half-mode gap waveguide cavity at the center frequency. Figure 4(a): Normalized E-plane radiation pattern at 26.5 GHz; (b): Normalized H-plane radiation pattern at 26.5 GHz; (c): Normalized E-plane radiation pattern at 29.5 GHz; (d): Normalized H-plane radiation pattern at 29.5 GHz; (e): Normalized E-plane radiation pattern at 32 GHz; (f): Normalized H-plane radiation pattern at 32 GHz. Detailed Implementation

[0020] The embodiments of the present invention will now be described with reference to the accompanying drawings. The embodiments shown in the drawings are merely exemplary and intended to explain the principles of the present invention, and are not intended to limit the scope of the present invention.

[0021] like Figure 1 As shown, this invention proposes an in-band full-duplex filtering antenna based on a half-mode gap waveguide cavity, including a pin layer (100), a cavity layer (200), and a ground plane (300). The cavity layer (200) and the pin layer (100) are separated by an air gap to form an electromagnetic bandgap (EBG) structure. The ground plane (300) is disposed on the lower surface of the pin layer (100). A side metal plate (400) is connected to the side of the cavity layer (200) through a WR32 waveguide (500).

[0022] Furthermore, the pin layer (100) is composed of periodically arranged metal pins (110) forming an artificial magnetic conductor AMC, thus creating an electromagnetic bandgap EBG structure.

[0023] Furthermore, the cavity layer (200) includes a half-mode gap waveguide TM mode resonant cavity (210), an H-plane rectangular radiating slot (220), and two E-plane rectangular radiating slots (230). The TM mode resonant cavity (210) is located at the horizontal geometric center of the cavity layer. One end of the H-plane rectangular radiating slot (220) is vertically connected to the upper surface of the half-mode gap waveguide TM mode resonant cavity (210), and the other end is connected to the radiating surface of the cavity layer (200). One end of the two E-plane rectangular radiating slots (230) is vertically connected to the upper surface of the half-mode gap waveguide TM mode resonant cavity (210), and the other end is connected to the radiating surface of the cavity layer (200). The two E-plane rectangular radiating slots (230) are symmetrically distributed on both sides of the H-plane rectangular radiating slot (220).

[0024] Furthermore, the rectangular slot in the middle of the ground plane (300) serves as the first channel feed port, and the rectangular slot in the middle of the ground plane (300) corresponds to the opening on the pin layer (100). The first channel feed port is symmetrical about the cavity layer (200) and is used to excite the TM mode resonator (210) of the half-mode gap waveguide vertically upward.10，3 / 2 model.

[0025] Furthermore, the rectangular slot in the middle of the side metal plate (400) serves as the second channel feed port, which is spatially orthogonal to the first feed port; and the rectangular slot in the middle of the side metal plate (400) is directly connected to the side wall slot of the cavity layer (200); the second feed port is coupled and excited by the WR32 waveguide (500) through the side wall slot of the cavity layer (200) to the TM mode resonator of the half-mode gap waveguide TM mode resonator (210). 20，1 / 2 model.

[0026] Furthermore, the first channel feed port and the second feed port are geometrically positioned at a 90° angle to achieve orthogonal polarization excitation.

[0027] Furthermore, the dimensions of the H-plane rectangular radiation slot (220) are adjustable, allowing for independent adjustment of the resonant slot mode frequency and TE. 10 Mode frequency.

[0028] Furthermore, the assembly configuration of the pin layer (100) and the cavity layer (200) is interchangeable. By adjusting the arrangement of the metal pins (110) in the pin layer, the three functions of broadband, bandstop, or IBDF can be switched.

[0029] This embodiment is based on a half-mode gap waveguide cavity. Its core physical principle is to cut off half of a traditional rectangular cavity along its longitudinal plane of symmetry. A periodic array of metal pins covers the remaining half-cavity, with only a 0.4mm air gap between the pin array and the cavity wall, forming a two-dimensional electromagnetic bandgap. Any transverse surface waves are suppressed, and energy is firmly locked within the half-cavity, propagating along a specified mode. Since there is no metal contact between the pin layer and the cavity layer, electrical contact loss in the millimeter-wave band is completely eliminated. Furthermore, mechanical assembly only requires screw tightening, eliminating the need for traditional waveguide countersinking, conductive adhesive, or welding processes, significantly reducing processing and maintenance costs. The three-dimensional dimensions retained inside the cavity, optimized by CST, are 7.8mm × 11mm × 5.8mm, perfectly supporting TM. 10,3 / 2 With TM 20,1 / 2 The two orthogonal modes resonate at the same frequency; the bottom port is directly fed into the TM through an 8.64mm × 4.32mm WR32 standard waveguide port. 10,3 / 2The sidewall ports are fed into the TM20 1 / 2 mode via a 2.2mm × 1.4mm coupling window. The two modes are spatially orthogonal and polarized orthogonal, with measured port isolation exceeding 44dB. Two radiating slots are located on the top and sidewalls, respectively. A pair of 1mm diameter, 1mm high perturbation pins symmetrically arranged along the z-axis center allow for precise fine-tuning of the resonant frequencies of the two modes without mutual interference, ensuring independent optimization of both channels at any frequency point within the 26.5–40GHz range. Function switching is achieved simply by changing the pin layer pattern: the broadband version retains all pins and the maximum coupling window; the bandstop version adds an additional perturbation pillar within the cavity to excite the TE. 110 Notch filtering is generated; the IBDF version is the embodiment of this example, requiring no hardware modifications. All three functions share the same cavity layer, significantly shortening the development cycle and reducing mold costs. The entire component uses SLA 3D printing of a photosensitive resin preform, followed by 3μm of chemical copper plating, then 5μm of copper plating, 1μm of nickel plating, and 0.1μm of gold plating. The printing accuracy is ±50μm. Layers are secured with M2 stainless steel screws at a torque of 0.5 N·m. The actual measured weight of the entire unit is 28g, and its dimensions are 15mm × 12mm × 8mm. Different modes achieve independent control through lateral coupling topology, avoiding mutual interference. The designed filter antenna structure diagram is shown below. Figure 1 As shown, its specific dimensions are shown in Table 1 (unit: mm):

[0030] Table 1

[0031] a g h p t <![CDATA[h w ]]> <![CDATA[l w ]]> 1.2 0.4 2.5 2.6 1 4 7.8 <![CDATA[l2]]> <![CDATA[w2]]> <![CDATA[l p ]]> <![CDATA[w p2 ]]> <![CDATA[l p2 ]]> <![CDATA[l s2 ]]> <![CDATA[l s3 ]]> 7.8 12 8.64 8 2.2 5.5 5.4 <![CDATA[w s2 ]]> <![CDATA[w s3 ]]> <![CDATA[h s2 ]]> <![CDATA[h s3 ]]> <![CDATA[b1]]> <![CDATA[c1]]> <![CDATA[d1]]> 1.5 1.9 5.9 1.4 1 3 1

[0032] Where a is the width of the pin; g is the air gap thickness; h is the height of the pin; p is the center-to-center distance between adjacent pins; t is the thickness of the pin layer; h w The height of the HMGGWTM mode resonator in the half-mode gap waveguide; l w l1 is the length of the H-plane rectangular radiating slot; l2 is the length of the half-mode gap waveguide HMGGWTM mode resonant cavity; w2 is the width of the H-plane rectangular radiating slot; l p w is the length of the power supply port. p2 The width of the stepped transition section at the second channel feed port; p2 The length of the stepped transition section at the second channel feed port; l s2 The width of the rectangular radial groove in the H-plane; l s3 w is the length of the rectangular radiating slot in the E-plane. s2 The height of the rectangular radial trough in the H-plane; w s3 h is the width of the rectangular radial groove in plane E; s2 h is the height of the H-plane rectangular radiation slot from the lower surface of the cavity; s3 b1 is the height of the rectangular radiation slot in plane E from the lower surface of the cavity; c1 is the depth of the disturbance structure; d1 is the height of the disturbance structure from the lower surface of the cavity; and d1 is the height of the disturbance structure.

[0033] Figure 3 These are the simulation and measured results of the reflection coefficient and gain curve of the in-band full-duplex filtered antenna described in this invention. The center frequency of both channels is 29.5 GHz. The 10 dB impedance bandwidth range is 27.4 to 31.6 GHz for the first channel and 27.7 to 31.4 GHz for the second channel, with FBWs of 14.1% and 12.5%, respectively. Furthermore, the in-band gain of the first channel exceeds 6.4 dBi, the in-band gain of the second channel exceeds 10.3 dBi, and the inter-channel isolation is better than 44 dB. Figure 4 This is the radiation pattern of the in-band full-duplex filtering antenna based on a half-mode gap waveguide cavity described in this invention at the center frequency. Results show that the normalized cross-polarization level is below -18dB in both channel cases, meeting the requirements for high integration and reconfigurable RF front-end in 5G / 6G millimeter-wave small base stations, backhaul links, and satellite terminals.

[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, chip, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, chip, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, chip, article, or apparatus that includes said element.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A multifunctional broadband filtering antenna based on a half-mode gap waveguide cavity, characterized in that, It includes a pin layer (100), a cavity layer (200), and a ground plane (300). The cavity layer (200) and the pin layer (100) are separated by an air gap to form an electromagnetic bandgap (EBG) structure. The ground plane (300) is disposed on the lower surface of the pin layer (100). A side metal plate (400) is connected to the side of the cavity layer (200) through a WR32 waveguide (500).

2. The multifunctional broadband filtering antenna based on a half-mode gap waveguide cavity according to claim 1, characterized in that, The pin layer (100) is composed of periodically arranged metal pins (110) forming an artificial magnetic conductor AMC, thus creating an electromagnetic bandgap EBG structure.

3. The multifunctional broadband filtering antenna based on a half-mode gap waveguide cavity according to claim 1, characterized in that, The cavity layer (200) includes a half-mode gap waveguide TM mode resonant cavity (210), an H-plane rectangular radiating slot (220), and two E-plane rectangular radiating slots (230). The TM mode resonant cavity (210) is located at the horizontal geometric center of the cavity layer. One end of the H-plane rectangular radiating slot (220) is vertically connected to the upper surface of the half-mode gap waveguide TM mode resonant cavity (210), and the other end is connected to the radiating surface of the cavity layer (200). One end of the two E-plane rectangular radiating slots (230) is vertically connected to the upper surface of the half-mode gap waveguide TM mode resonant cavity (210), and the other end is connected to the radiating surface of the cavity layer (200). The two E-plane rectangular radiating slots (230) are symmetrically distributed on both sides of the H-plane rectangular radiating slot (220).

4. A multifunctional broadband filtering antenna based on a half-mode gap waveguide cavity according to claim 3, characterized in that, The rectangular slot in the middle of the ground plane (300) serves as the first channel feed port, and the rectangular slot in the middle of the ground plane (300) corresponds to the opening on the pin layer (100). The first channel feed port is symmetrical about the cavity layer (200) and is used to excite the TM mode resonator (210) of the half-mode gap waveguide vertically upward. 10，3 / 2 model.

5. A multifunctional broadband filtering antenna based on a half-mode gap waveguide cavity according to claim 4, characterized in that, The rectangular slot in the middle of the side metal plate (400) serves as the second channel feed port, which is spatially orthogonal to the first feed port; and the rectangular slot in the middle of the side metal plate (400) is directly connected to the side wall slot of the cavity layer (200); the second feed port is coupled and excited by the WR32 waveguide (500) through the side wall slot of the cavity layer (200) to the TM mode resonator of the half-mode gap waveguide TM mode resonator (210). 20，1 / 2 model.

6. A multifunctional broadband filtering antenna based on a half-mode gap waveguide cavity according to claim 5, characterized in that, The first channel power supply port and the second power supply port are geometrically 90° apart to achieve orthogonal polarization excitation.

7. A multifunctional broadband filtering antenna based on a half-mode gap waveguide cavity according to claim 1, characterized in that, The dimensions of the H-plane rectangular radiation slot (220) are adjustable, allowing for independent adjustment of the resonant slot mode frequency and TE. 10 Mode frequency.

8. A multifunctional broadband filtering antenna based on a half-mode gap waveguide cavity according to claim 1, characterized in that, The assembly configuration of the pin layer (100) and the cavity layer (200) is interchangeable. By adjusting the arrangement of the metal pins (110) in the pin layer, the three functions of broadband, bandstop, or IBDFD can be switched.

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