Nonlinear Monolithic Circuits in Coplanar Waveguide Technology for Receiver Applications up to 55 GHz

Nonlinear circuits including oscillators, frequency doublers and mixers were designed and fabricated in coplanar waveguide. techhology. For the design commercial CAD software was used with an implemented in-house nonlinear MODFET model for the active device. The 27 GHz to 54 GHz frequency doubler achieves a conversion loss of 8 dB at an input power of 5 dBm. A buffer amplifier suppresses the fundamental frequency and amplifies the doubled frequency at 54 GHz by 10 dB, thus giving a resulting conversion gain of about 2 dB. A very broadband distributed mixer was developed operating over 10 - 50 GHz RF-bandwidth with IF frequencies from several MHz to 5 GHz. The conversion gain is better than - 3 dB over the frequency range without IF amplification. A broadband distributed combiner is used to feed the RF and LO signals with an LO to RF port isolation of 20 dB.