Date of Graduation

12-2012

Document Type

Thesis

Degree Name

Master of Science in Microelectronics-Photonics (MS)

Degree Level

Graduate

Department

Graduate School

Advisor

Magda O. El-Shenawee

Committee Member

Ken G. Vickers

Second Committee Member

Douglas A. Hutchings

Abstract

This thesis describes the origins, improvements, and variations of a broadband microwave antenna that can be beam-steered by a micro-electromechanical system (MEMS). The steerable MEMS antenna of this work was comprised of a planar antenna on top of a Silicon membrane. The membrane is etched to create a gimbal hinge structure and a platform which supported the antenna and gave it one or two degrees of freedom of rotation. The antennas presented were broadband and fed by a coplanar waveguide (CPW) transmission line which traversed the hinge structure. The antenna's orientation in space was designed to be changed through electrostatic actuation of the antenna platform's hinges.

The goal of this thesis was to improve on the initial design and performance of the prototypic antenna. The best variation of the prototype antenna could rotate ±4.0° in two degrees of freedom under 800 VDC of actuation voltage and had a bandwidth of 1.55. The mechanical and electrical aspects of the device were studied and analyzed concurrently. Three variations of the MEMS antenna platform were design and modeled; Generations 1 - 3 (G1 - G3). The G1 platform was an optimized version of the prototypic MEMS platform. The G2 platform could rotate in two dimensions but had much thinner hinges and a more robust antenna platform. The G3 platform was a one degree of freedom version of the G2 platform. A new antenna shape was selected and optimized for integration with the three generations of antenna platforms; the planar inverted cone antenna (PICA). The G3 platform had the best overall electrical and mechanical performance. Two additional antennas were simulated on the G3 platform; a cylindrical dielectric resonator antenna (C-DRA) and a teardrop dielectric resonator antenna (Td-DRA). The three best antenna variations on the G3 platform were simulated to have maximum actuation

angles ranging from 10 - 13° and have bandwidths of 3.62 (PICA), 1.70 (C-DRA), and 1.78 (Td-DRA).

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