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Proceedings Paper

Integrated micromachined transmission lines and endfire slotline antennas
Author(s): Steven S. Gearhart; Theodore L. Willke; Eko N. Onggosanusi
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Paper Abstract

An entirely new class of micromachined 3D microwave and millimeter-wave integrated circuits and antennas are being developed at the University of Wisconsin-Madison using a subset o the LIGA micromachining process. The deep x-ray lithography and metal plating portions of the LIGA process are used to precisely form tall metal structures on semiconductor and dielectric substrates. This micromachining process allows metal height to be included as a parameter in the design of integrated circuits, which will permit several important advancements in high frequency waveguiding circuits and integrated antennas. With appropriate thick- metal cross-sectional geometry, transmission line losses and dispersion may both be reduced on a given substrate. Vertical-walled metal structures allow increased control over element-to-element coupling for integrated coupled-line filters and couplers and result in very significant reductions in ohmic loss. It will be demonstrated that the first single-level coupled-line 3dB coupler can be fabricated using the LIGA process. In addition, the mechanical properties of the thick metal structures will be utilized in the fabrication of integrated antennas and transmission lines that are unsupported by a dielectric substrate. The elimination of the substrate beneath antennas reduces losses to substrate modes, and the elimination o the substrate beneath transmission line filters is necessary for extremely high Q integrated filters. This paper will present simulated loss results that demonstrate the advantages of thick metal transmission lines, measured results of a coupled-line bandpass filter, and a recently fabricated thick-metal tapered slotline antenna which extends nearly a centimeter off of the edge of a GaAs wafer.

Paper Details

Date Published: 2 September 1997
PDF: 10 pages
Proc. SPIE 3225, Microlithography and Metrology in Micromachining III, (2 September 1997); doi: 10.1117/12.284547
Show Author Affiliations
Steven S. Gearhart, Univ. of Wisconsin/Madison (United States)
Theodore L. Willke, Univ. of Wisconsin/Madison (United States)
Eko N. Onggosanusi, Univ. of Wisconsin/Madison (United States)

Published in SPIE Proceedings Vol. 3225:
Microlithography and Metrology in Micromachining III
Craig R. Friedrich; Akira Umeda, Editor(s)

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