CN-122026133-A - Low-sidelobe waveguide filtering slot array antenna for 5G millimeter waves and working method

Abstract

The invention provides a low-sidelobe waveguide filtering slot array antenna for 5G millimeter waves and a working method thereof, belonging to the field of communication systems. The antenna is formed by sequentially connecting an input port, a front-stage filter resonator group and a final-stage composite resonator in series. The top surface of the final-stage composite resonator is provided with a plurality of rectangular radiation gaps to form a radiation array, and the cavity is simultaneously used as the last-stage resonance unit of the filter to realize the deep fusion of the filtering function and the radiation function. The invention eliminates cascading loss by integrally designing the final-stage filtering resonant cavity and the radiation slit, remarkably improves the system efficiency, precisely controls the slit offset by utilizing a Taylor synthesis method, realizes the low side lobe level of-20 dB, and solves the low-cost manufacturing problem of a complex structure by adopting a 3D printing process. The invention is suitable for the 5G millimeter wave device with 28 GHz frequency bands, and has high integration level, high performance and good manufacturability.

Inventors

• HUANG TAOTAO
• XU XINYUAN
• SU WENBO
• ZHANG JIALE
• LI RONGJIN
• GAO CHAN

Assignees

• 西安邮电大学

Dates

Publication Date

20260512

Application Date

20260317

Claims (10)

1. 1. The low-sidelobe waveguide filtering gap array antenna for the 5G millimeter waves is characterized by comprising a three-dimensional metal cavity structure, wherein the three-dimensional metal cavity structure comprises an input waveguide port (2), a front-stage filtering resonator group (4) and a final-stage composite resonator (6) which are sequentially connected in series, the input waveguide port (2) is connected with the front-stage filtering resonator group (4) through an input coupling diaphragm (3), the front-stage filtering resonator group (4) is connected with the final-stage composite resonator (6) through an inductive coupling diaphragm (5), a plurality of radiation gaps (7) are periodically formed in the top surface of the final-stage composite resonator (6) along the length direction, and the formed rectangular radiation gaps (7) form a radiation array.
2. 2. A low side lobe waveguide filter slot array antenna for 5G millimeter waves according to claim 1, characterized in that the pre-stage filter resonator group (4) comprises a first rectangular resonator (41) and a second rectangular resonator (42) which are connected in series, the first rectangular resonator (41) and the second rectangular resonator (42) being connected by an inductive coupling membrane (5).
3. 3. A low side lobe waveguide filter slot array antenna for 5G millimeter wave according to claim 2, characterized in that the length of the final stage composite resonator (6) is larger than the length of the preceding stage filter resonator group (4).
4. 4. A low side lobe waveguide filter slot array antenna for 5G millimeter waves according to claim 2, characterised in that the first rectangular resonator (41) and the second rectangular resonator (42) are rectangular metal cavities.
5. 5. A low side lobe waveguide filter slot array antenna for 5G millimeter waves according to claim 2, characterized in that the internal height of the first rectangular resonator (41) and the second rectangular resonator (42) is identical to the size of the standard waveguide WR-34, and the size of the input waveguide port (2) is identical to the size of the standard WR-34 waveguide.
6. 6. A low side lobe waveguide filter slot array antenna for 5G millimeter waves according to claim 1, characterized in that the final stage composite resonator (6) is a composite resonator with both filtering and radiating functions.
7. 7. A low side lobe waveguide filter slot array antenna for 5G millimeter waves according to claim 1, characterised in that the arrangement of the radiating slots (7) is of taylor distributed offset design.
8. 8. The low-side lobe waveguide filter slot array antenna for 5G millimeter wave according to claim 7, wherein the number of the radiation slots (7) is 5, and the radiation slots (7) are distributed symmetrically left and right with the 3 rd radiation slot (7) located at the middle position as the center.
9. 9. The low sidelobe waveguide filter slot array antenna for 5G millimeter waves of claim 8, wherein the specific offset of the Taylor distributed offset design is set as d 3 which is an upward offset of the 3 rd radiating slot (7) in the width direction, d 1 which is an upward offset of the 1 st radiating slot (7) and d 2 which is an downward offset of the 2 nd radiating slot (7) based on the 3 rd radiating slot (7), and the 4 th radiating slot (7) and the 1 st radiating slot (7) are offset from each other by symmetry.
10. 10. The working method of the low-sidelobe waveguide filtering slot array antenna for the 5G millimeter waves is based on any one of claims 1-9, and is characterized in that energy enters from an input waveguide port (2), is coupled between all levels of resonant cavities step by step through an input coupling diaphragm (3) and an inductive coupling diaphragm (5) and finally reaches a final-level composite resonator (6), the final-level composite resonator (6) serves as a final-level resonant unit of a filtering network, and a plurality of radiation slots (7) formed in the top surface of the final-level composite resonator (6) directly radiate electromagnetic energy outwards, so that the deep fusion of a filtering function and a radiation function is realized.

Description

Low-sidelobe waveguide filtering slot array antenna for 5G millimeter waves and working method Technical Field The invention belongs to the technical field of communication systems, and particularly relates to a low-sidelobe waveguide filtering slot array antenna for 5G millimeter waves and a working method thereof. Background With the commercial deployment of fifth generation (5G) mobile communication technologies, it has become one of the key technology paths to implement ultra-high rate data transmission (up to 10 Gbps) by using rich spectrum resources in the millimeter Wave (mm-Wave) frequency band (e.g., 24.25-29.5 GHz, 37-40 GHz). However, millimeter wave signals face severe physical challenges in propagation, including significant free space path loss, atmospheric attenuation, and susceptibility to obstruction, resulting in limited signal coverage and poor link stability. In order to overcome these bottlenecks, the adoption of high-gain and well-oriented antenna arrays at the transmitting end and the receiving end becomes a core means for compensating the link budget and improving the system capacity. Meanwhile, in a dense 5G network environment, in order to reduce co-channel interference and multipath effects, the radiation pattern of the antenna must have a low Side Lobe Level (SLL) characteristic to enhance the spatial selectivity and anti-interference capability of the system. In a conventional 5G rf front-end architecture, the antenna and the filter are typically designed in cascade as two separate modules. The discrete scheme has flexible design, but has a series of inherent defects that firstly, a feed network (such as a microstrip line, a coplanar waveguide or a probe) for connecting an antenna and a filter can introduce non-negligible conductor loss and dielectric loss, especially in a high frequency band such as 28 GHz, which directly reduces the radiation efficiency of the whole system, secondly, the existence of an interconnection structure is easy to cause impedance mismatch and parasitic coupling, influences the frequency response of the filter and the standing wave ratio of the antenna, further worsens the overall performance, and in addition, the stacking of discrete devices leads to the increase of the volume and the complexity of the structure of the radio frequency front end, so that the increasingly severe miniaturization, light weight and thin design requirements of 5G millimeter wave devices are difficult to meet. To solve the above problems, the concept of a filter antenna (FILTERING ANTENNA) has been developed. The filter antenna has the advantages that the filter function is directly embedded into the radiation structure of the antenna, so that the antenna has the dual functions of frequency selection and electromagnetic radiation, the insertion loss and matching problems caused by a cascade interface are effectively eliminated, and the system integration level and the energy conversion efficiency are improved. Currently, research on millimeter wave filter antennas is mainly focused on planarization structures. For example, microstrip patch-based filter antennas are attracting attention because they are easy to integrate with integrated circuits, but their high dielectric loss and surface wave loss in the millimeter wave band severely restrict the radiation efficiency and gain level, and it is difficult to achieve complex low side lobe pattern synthesis. Another type of mainstream scheme is a substrate integrated waveguide (Substrate Integrated Waveguide, SIW) filter antenna, which simulates the electromagnetic characteristics of a conventional metal waveguide by constructing a periodic through-hole array on a dielectric substrate, and has the advantages of lower transmission loss and planarization. However, the equivalent wall conductivity of the SIW structure is limited by the via gap and the processing precision, and there is still a certain ohmic loss, and more importantly, the working bandwidth is limited by the periodicity of the unit structure, the flexibility is insufficient, and the complicated feed network design further increases the size and the loss when pursuing lower side lobes. Thus, despite the advances made by existing planar filter antennas, there are still significant challenges in achieving a perfect balance of high efficiency, low side lobes, and small size. In contrast, conventional metal rectangular waveguide slot array antennas exhibit unmatched potential in the millimeter wave band. The full-metal closed cavity structure fundamentally avoids dielectric loss, has extremely low transmission loss and extremely high power capacity, and is very suitable for high-gain application. In addition, the precisely cut slits in the waveguide can produce highly directional main lobes and predictable radiation patterns, and the position, length and offset of the slits are optimized by Taylor (Taylor) or Chebyshev (Chebyshev) distribution theory, so that the level of