Broad-band 180° phase shifters using integrated submillimeter-wave Schottky diodes

A proof-of-concept broad-band 180° phase shifter operating at 220 GHz and based on planar integrated Schottky diodes is presented. The phase shifter is a monolithic implementation incorporating impedance transformers designed to yield broad-band operation and compensate for amplitude imbalance between bias states of the diodes. The circuit described in this paper has yielded a phase shift of 180°±15° over a 55-GHz band with average insertion loss of 5.5 dB. Moreover, the phase shifter is demonstrated and tested as a sideband generator where it has exhibited an average carrier-to-single sideband conversion loss of 10 dB. The circuit architecture is scalable to submillimeter frequencies where phase shifters are often employed for sideband generation and parametric upconversion.