Steady-State Thermal Analysis on a Real-Time Plasma Impedance Tuner for High-Power RF Matching Applications

With fifth generation (5G) wireless spectrum reallocation presenting an increasingly congested spectral environment, radar systems need to utilize the advantages of real-time high-power impedance tuners to reconfigure in real time for maximization of output power and detection range. The ability to analyze a low-loss plasma switched-network impedance tuner, previously demonstrated for high-power capability, is further developed for analysis of thermal failure. The goal is both to understand the thermal properties and limitations of the radio-frequency (RF) board of the tuner under impedance tuning conditions and to assess the thermal power handling capabilities of the tuner structure. Based on thermal failure, an approach for assessing power-handling capability is demonstrated using CST's 3-D Multiphysics solver for Electromagnetic (EM)-Thermal Coupled simulations. The EM simulator analyzes the current density across the structure and translates this current density into temperature through the electrothermal model. The thermal analysis shows at least 51.1 W of power handling over all tuner states and frequencies, given failure by solder reflow at 91.5°C. The results of this paper provide a framework for analysis of tuner thermal failure and assessment of power handling.