MEMS variable-capacitor phase shifters part I: Loaded-line phase shifter

Abstract

This article describes the design and characterization of a continuously variable loaded-line phase shifter using micro-electro-mechanical system (MEMS) variable capacitors as phase shifting components. The design and characterization of micro-electro-mechanical system (MEMS) variable capacitors for operation at 26.5 GHz is described. A lumped-element model is obtained from measurements and physical consideration. Experimental results show a capacitance-tuning ratio of 3.7:1. The capacitor's characterization results are used for designing the phase shifter. A phase shift of 40.5° at 26.5 GHz for a loaded-line type has been measured. There is good agreement between simulated and measured results. A companion article (Part II) describes the application of these variable capacitors to the design of reflection-type phase shifters. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 321–337, 2003.