Resonator Voltage Prediction in Microwave Bandpass Filters

The prediction of peak voltages in high-power bandpass filters is presented using a new method in order to overcome the limitations of previously reported techniques. The concepts of coupling matrix, frequency transformation, and resonator stored energy are used to arrive at a compact formulation, which accounts for both circuital and electromagnetic (EM) filter characteristics. The resulting expression is independent of the detailed filter design. An analytical method is therefore obtained, enabling RF power-handling studies of bandpass filters without restrictions on filter bandwidth or resonator geometry. Explicit formulas are derived and applied to examples representative of a variety of applications, i.e., rectangular-waveguide TE101-mode Chebyshev and coaxial TEM-mode Bessel filters. EM simulations and experimental results verify the validity of the presented method.