Design And Research Of High Performance Microwave Antenna Based On Substrate Integrated Waveguide

Substrate integrated waveguide（SIW）is a new type of guided wave structure,which has the advantages of high power capacity,easy integration with planar circuits and low processing cost,and is widely used in the design of functional devices such as microwave antennas.At present,microwave antennas based on SIW still have problems to be solved in terms of bandwidth broadening,multi-frequency response and circularly polarized radiation.Theoretical research and simulation optimization are carried out on bandwidth broadening,multi-frequency response and circularly polarized radiation,and experimental processing and testing are carried out.The specific research contents and work innovations are as follows:1.A broadband microwave antenna based on SIW is proposed,which solves the problem of narrow bandwidth caused by the low profile of the SIW.Using a SIW rectangular cavity as a resonator,and by designing a drum-shaped slot to excite higher-order mixed modes(odd-TE₁₂₀and even-TE₁₂₀),and introducing a set of short-circuit vias in the antenna cavity to disturb the electric field of the fundamental mode,the bandwidth of the antenna is expanded.The theoretical analysis and simulation optimization of the designed antenna are carried out,and the experimental processing and testing are carried out.The experimental results are basically consistent with the simulation results.The antenna works in the X-band,and its fractional bandwidth reaches 23.5%,and the gain is stably maintained within the range of 5.6dBi to 6.48dBi,the maximum cross-polarization level is less than-26dB.2.A dual-frequency microwave antenna based on SIW is proposed,which provides a new idea for multi-frequency antenna design by exciting multiple high-order modes.The SIW rectangular cavity is used as the resonator,and a group of fan-shaped patches is added to the circular slot on both sides of the dumbbell-shaped slot to form a modified dumbbell-shaped slot to achieve dual-frequency response.The opening angle and offset angle of different sector patches can cause the offset of the dual-frequency response frequency band,then the antenna working frequency band can be freely designed within a certain frequency band,which improves the flexibility of the antenna design.The theoretical analysis and simulation optimization of the designed antenna are carried out,and the experimental processing and testing are carried out too.The experimental results are basically consistent with the simulation results.The antenna works in the X-band and Ku-band,and the fractional operating bandwidths tested in the two bands are 6.06%（9.6GHz-10.2GHz）and 1.41%（14.06GHz-14.26GHz）,respectively,and the simulated maximum gains in the low-frequency and high-frequency operating bands are 5.9dBi and 6.13dBi,respectively.3.A circularly polarized microwave antenna based on SIW is proposed,which provides a new design scheme for realizing circularly polarized radiation.The SIW rectangular cavity is used as the resonator,and two orthogonal modes in the resonator are excited by adding four groups of small rectangular slits around the square ring slit to generate right-handed circularly polarized waves.The theoretical analysis and simulation optimization of the designed antenna are carried out,and the experimental processing and testing are carried out too.The experimental results are basically consistent with the simulation optimization results.The antenna works in the X-band,and its tested fractional operating bandwidth is 19.1%（9.8GHz-11.87GHz）,the simulated axial ratio bandwidth（less than-3dB）is 16%,and the maximum gain in the working frequency band is 7dBi.