Study And Design Of Miniaturized Microwave And Millimeter Wave Circularly Polarized Antenna

In recent years,compared with linear polarization antennas,circular polarization antennas have been widely used in satellite communications,navigation systems,mobile communications,and other fields due to their unique advantages of reducing polarization losses and resisting multipath fading.With the development of modern communication technology,people have increasingly high requirements for antennas,which not only require superior performance and diverse functions,but also pursue miniaturization and portability.Therefore,it is of great significance and application value to study the miniaturization and multi-frequency of antennas.In this thesis,the study and design of circularly polarized antennas in the microwave and millimeter wave frequency bands are mainly carried out.In the research process,theoretical analysis,software simulation design,and experimental verification methods are adopted.A compact and low-profile circularly polarized antenna based on low-temperature co-fired ceramic（LTCC）technology for the application of 5G millimeter-wave,and a Ku band satellite communication miniaturized dual frequency dual circular polarization antenna are proposed.The main work content is:1.A circularly polarized millimeter-wave antenna based on low temperature cofired ceramic（LTCC）technology for the 5G millimeter-wave n257 frequency band application is designed,which realizes compact size and low-profile performance.The antenna structure utilizes a pair of L-shaped patches as the main radiation units.Additionally,parasitic loading technology is employed to expand the circularly polarized bandwidth of the antenna.The feeding mechanism adopts a grounded coplanar waveguide transition to substrate integrated waveguide（GCPW-SIW）structure.The antenna has the characteristics of compact structure and low-profile with the size of 0.58λ₀x 0.58λ₀x 0.056λ₀.The simulation results show that the antenna operates at a frequency of 26.5GHz-29.5GHz and a peak gain of 6.7d Bic under the conditions of|S₁₁|<-10d B and AR<3d B.In addition,an antenna sample was manufactured and tested to further verify the correctness of the antenna structure design.The test results are basically consistent with the simulation ones,indicating that the antenna has potential application value in 5G millimeter wave n257（26.5GHz-29.5GHz）frequency band communication and satellite communication systems.2.A miniaturized Ku band stacked antenna with the feature of dual frequency dual circular polarization is designed.The antenna exhibits a dual-band resonance,featuring a center operating frequency of 12.5GHz for the lower frequency band and a center operating frequency of 14.25GHz for the higher frequency band.The designed antenna adopts two radiation patches which are placed on two layers substrate respectively to achieve circularly polarized waves with different rotation directions.Specifically,the radiation unit in the low frequency band utilizes a square chamfered patch to realize right-handed circularly polarized radiation,while the high frequency portion selects a square patch with a diagonal narrow slot to obtain left-handed circularly polarized radiation.Furthermore,several slots are introduced at the edges of the two radiation patches to increase the current path,thus reducing the size of the antenna.The size of the antenna structure is:0.38λ₀x 0.38λ₀x 0.038λ₀.It has the advantages of miniaturization and simple structure.