Research On Analysis And Optimal Methods For RF And Thermal Performance Of RF Coaxial Relays

Radio Frequency (RF) coaxial relays are widely used in broadcast andtelecommunication industry. Because of their coaxial shielding structures, RF coaxialrelays have excellent ability of transmitting broadcast signals, and have characteristicsof low Insertion Loss, low Voltage Standing Wave Ratio (VSWR), high powercapability and high operating frequencies. Due to the rapid growth of modern broadcastand telecommunication systems, frequencies and powers of the signals transited aresoaring, which requires RF coaxial relays possess better transmission, isolation, thermalperformance in broadband to fulfill the pressing demand. Therefore, research isconducted to invest in theoretical analysis and simulation calculation of RF coaxialrelays to improve the theoretical level of RF coaxial relays of our country.In this paper, the operating principle of RF coaxial relays is analyzed first. Becauseof irregular structures and discontinuous impedances, FEM models of multi-physicsfield involving electromagnetic, thermal and structure fields are built to research on RFand thermal performance of the relay with FEM software ANSYS Workbench. Thesimulation result is examined by experiments.Furthermore, the influences the structures and material properties of the coaxialstructure, the spring and the contact area of the relay have on RF performance areresearched. The RF performance is improved and the impedance discontinuities arereduced by optimizing structure design and material selections using theoreticalcalculation and simulation analysis.Afterwards, to solve the problem of RF performance degeneration due to thermalissues caused by high power of the signals transmitted, thermal performance of the relayis analyzed with the multi-physics field simulation tool ANSYS Workbench Anequivalent experiment is designed to test the analysis result. Thermal performance isimproved by analyzing the failure modes, failure reasons and the influence factors ofpower capability of the relay.At the last, this paper analyses the influence the manufacturing processes has onRF performance of the relays. At the meantime, the tolerance design is performed toreassign the tolerances based on contribution rates and related RF component standards.The tolerance design helps manufacturers reduce the producing cost while RFperformance dispersivity is under controlled and provides a basis for producing RFcoaxial relays.