MEMS 75-110 GHz phase shifters
KTH has developed a new MEMS phase-shifter concept, based on a moving dielectric block on-top of a micromachined transmission line. This concept has proven to have better RF performane in terms of phase-shift per loss and reflections over the whole W-band, as compared to the conventional RF MEMS phase-shifter concepts (distributed MEMS transmission-line, DMTL, and MEMS switched true-time delay lines, TTD) and as compared to any other transmission-line based phase shifter concept at W-band. It was published in 2009 and still (2014) presents the the world's best W-band phase shifter performance, in terms of insertion loss per bit (3 and 4.25 bit phase shifters were implemented), phase shift per dB loss, and return loss, and keeps this excellent performance over the whole W-band.
Furthermore, this concept has by far increased power handling capability, as no thin metallic bridges, limiting the power dissipation in the device, are employed. Thus, this is the only MEMS phase shifter concept where not the MEMS part is limiting the power handling, but the power handling is limited only by the transmission line alone. 1 billion cycles reliability was presented.
The research work won the Best Paper Award at the IEEE European Microwave Integrated Circuit Conference 2009, Rome, Italy, and two Graduate Fellowships of the IEEE Microwave Theory and Technique Society (MTT-S) in 2010 and 2011.
Key Publicatiions:
Funding:
NORDITE Scandinavian ICT Programme (VINNOVA, TEKES, RCN), 2006-2010
People involved:
Nutapong Somjit (former PhD student, now at Leeds university)
Joachim Oberhammer (project leader)