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IEEE Microwave and Guided Wave Letters
Volume 10 Number 4, April 2000

Table of Contents for this issue

Complete paper in PDF format

Low-Loss Cascadable MEMS Distributed X-Band Phase Shifters

Joseph S. Hayden and Gabriel M. Rebeiz

Page 142.

Abstract:

A wideband distributed coplanar-waveguide (CPW) phase shifter has been developed for X-band operation. The design is based on the distributed MEMS transmission line (DMTL) loaded with high capacitance-ratio varactors. The varactors are fabricated using a series combination of MEMS bridges and fixed-value MIM capacitors. A high-capacitance ratio varactor (1.5-2.5) results in a large loading on the CPW line and therefore a large phase shift. A distributed phase shifter was fabricated on a 500 µm quartz substrate, and achieved a true-time delay operation from 1 to 10 GHz with a reflection coefficient less than -15 dB, and 180° /dB of insertion loss at 8-10 GHz. It is possible with this design to cascade the DMTL to result in 2-and 3-bit phase shifters with excellent wideband performance at X-band frequencies.

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