Millimetre-wave phase modulators with lumped-element circuitry

P.M. and a.m. puke modulators for millimetre waves are described that have been realised using a waveguide below-cutoff technique. This technique is well suited to the establishment of lumped elements of low loss, even in the millimetre wave region. Performance data of a 34 GHz phase modulator are a bandwidth of 12%, an insertion loss of 0.5 dB and switching times below 1 ns. An on-off switch shows 0.5 dB and more than 20 dB losses, respectively, over a 1 GHz frequency band.