A 60 to 96 GHz fast-acting plasma waveguide switch

A fast-acting millimeter-wave switch has been developed that uses an argon-hydrogen plasma as the active element and has a high switching ratio over the 60 to 96 GHz frequency band. Measurements using low-amplitude electromagnetic probing waves have shown isolation to be over 40 dB at moderate plasma densities and over 60 dB at high plasma densities. Cold loss and VSWR are under 1 dB and 1.2, respectively. The time required for the r-f isolation to rise from cold loss to 20 dB (the switch-on time) is 2 microseconds and the time required for the r-f isolation to fall from 20 dB to 3 dB (the switch-off time) is 2 microseconds. Carefully measured isolation values at low plasma density ( /cm³) were extrapolated to show that isolation of 70 dB at 75 GHz and 35 dB at 90 GHz is achieved.