An in situ tunable diode mounting topology for waveguide switches is presented and utilized to design and fabricate two evanescent-mode -band switching modules of approximately 15% and 25% fractional bandwidth. The ability of the mounting topology to operate in a high-power environment is verified in an evanescent-mode -band switch using six packaged p-i-n diodes, successfully reflecting 4 kW of pulsed power.Index Terms-Diode mount, evanescent mode, high power, p-i-n diodes, waveguide switch, -band.