Millimeter-wave integrated phase shifters using planar Schottky barrier diodes

RF and microwave wireless communications has been an area of dramatic growth over the last decade. Under a proper system design, the data rate for a wireless system is mainly bottlenecked by its bandwidth. It is obvious that the need for more bandwidth has been pushing the operating frequencies of wireless systems higher and higher. It is expected that this trend will continue into the millimeter wave band (30 GHz∼300 GHz) and further as wireless systems generate more applications and higher data rate communication links are demanded.; Phase shifters are essential elements in communication networks and are used as phase modulators and frequency up-converters (also known as side-band generators) in the RF front-ends of wireless systems. In this dissertation, several phase-shifter circuits for millimeter wave applications are investigated. This research has culminated in the design, fabrication and testing of a wideband phase shifter MMIC that is based on a balanced circuit architecture with integrated Schottky diodes and operates in the upper end of the millimeter wave spectrum. In addition, two other novel phase shifter architectures based on Lange couplers have been proposed, implemented, and studied.; The balanced phase shifter MMIC is, to our knowledge, the first reported transmission-type phase shifter MMIC operating above 200 GHz. This work extends the application domain of the Schottky-diode-based MMIC technology from mixers and power sources to control circuits. The phase shifter MMIC can be utilized as a BPSK modulator or a frequency up-converter in RF front ends of wireless systems operating at the upper end of the millimeter wave region. The phase shifter MMIC can be also utilized as a transmission-type varactor sideband generator for frequency tunable power sources with sideband conversion losses comparable to previously demonstrated reflection-type counterparts that operate in approximately same frequency range. The circuit architecture described in this work can be potentially scaled up to the terahertz region (where frequency tunable power sources are scarce).