Graduation Year

2005

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Electrical Engineering

Major Professor

Dr. Tom Weller.

Co-Major Professor

Co-adviser:

Keywords

Tunable, Transmission lines, Phased array, Calibration, Slow-wave

Abstract

A true time delay multi-bit MEMS phase shifter topology based on impedance-matched slow-wave CPW sections on a 500 m thick quartz substrate is presented. Design equations based on the approximate model for a distributed line is derived and used in optimization of the unit cell parameters. A semi-lumped model for the unit cell is derived and its equivalent circuit parameters are extracted from measurement and EM simulation data. This unit cell model can be cascaded to accurately predict N-section phase shifter performance. Experimental data for a 4.6mm long 4-bit device shows a maximum phase error of 5; and S11 less than -21dB from 1-50GHz. A reconfigurable MEMS transmission line based on cascaded capacitors and slow-wave sections has been developed to provide independent Zo - and -tuning. In the Zo-mode of operation, a 7.4mm long line provides Zo-tuning from 52 to 4 (+/-2;) with constant phase between the states through 50GHz.

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