Research On Passive Intermodulation Of Coaxial Connector Under Multiphysics Effect

Coaxial connectors are widely used in various communication systems,and play an irreplaceable role in information exchange or energy transmission between circuits and microwave components.With the increasing popularity of high-power communication systems,PIM issues in coaxial connectors have attracted more and more attention.Due to the increasingly complex application scenarios,the PIM products of the coaxial connector will be affected by external environmental factors,showing the characteristics of Multiphysics field effect coupling,making it more difficult to predict.Therefore,this paper starts from the study of the electrical and structural characteristics of the coaxial connector under the Multiphysics effect,and proposes a PIM power level prediction model for the coaxial connector with the Multiphysics effect and performs experimental verification,and the prediction error is within ±3 d B.The article is divided into the following parts for research:1.Research on the electrical and structural characteristics of the coaxial connector under Multiphysics effect.The electrical characteristics such as electromagnetic field strength,S-parameters,and structural characteristics such as deformation and contact pressure of the coaxial connector will be affected by factors such as carrier power,ambient temperature,and external load,resulting in the appearance of nonlinear characteristics.Therefore,using the lumped circuit model and finite element simulation,the fitting expression of lumped resistance,carrier power,and ambient temperature is solved.Using finite element simulation,the fitting expression of contact pressure,ambient temperature,and torque is solved.2.Research on the analytical model of PIM power level under the Multiphysics effect of the coaxial connector.The PIM of coaxial connectors will be affected by complex external factors,making the PIM products under the Multiphysics effect more difficult to predict.Therefore,based on the electrical contact theory,the contact resistance of the coaxial connector under the Multiphysics effect is solved.Based on the reducedorder compact thermal circuit model,the electro-thermal coupling effect of the coaxial connector is characterized.By combining contact resistance and electro-thermal coupling,an analytical prediction model of PIM under the Multiphysics effect of the coaxial connector is obtained,and the relationship between the PIM of the coaxial connector and the carrier power,temperature and torque is considered.3.Experimental verification of PIM power level analytical model under Multiphysics effect of the coaxial connector.Due to the randomness and complexity of PIM products under Multiphysics effect,this paper introduces the DOE method to design experimental schemes to reduce the influence of random errors.With DIN-type and Ntype connectors as the test objects,the reflective PIM test system was used to test the PIM power levels under different combinations of input power,temperature,and torque parameters,and a DOE fitting model was obtained.By comparing the predicted value of the DOE fitting model and the measured data with the predicted value of the proposed analytical model,the error is within ±3d B,which verifies the effectiveness of the proposed analytical prediction model.It reveals the change rule of PIM power level under different input power,temperature and torque conditions of coaxial connector.