An "O" Band Fast PIN Diode Switch

An "O" band fast PIN diode SPST switch has been developed which has an insertion loss ⩽ 1.0 dB and an isolation ⩾ 25 dB over a 5% bandwidth. Switching speed is < lns and estimated power handling is ⩾ 1 watt c.w. The unit is to be used as a modulator in a 60 GHz, 130 megabit/see digital radio data link under development at RSRE Malvern. The active element is a gold doped P+NN+ diode which is switched in a resonant mode as discussed by Garver (1). An inductive strap is used to series resonate the reverse biased diode and this is connected to a quartz standoff which is mounted across a section of single ridge guide. Tchebycheff, ridge guide, impedance transformers match the section to WG25/WR15 guide. To obtain increased isolation bandwidth a two diode cavity is being developed and the final switches will be integrated with a driver to keep switching time and delay to a minimum.