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Silicon bulk micromachined waveguide resonators and filters

Posted on:2007-05-22Degree:Ph.DType:Thesis
University:University of Toronto (Canada)Candidate:Stickel, Micah TFull Text:PDF
GTID:2448390005975353Subject:Electrical engineering
Abstract/Summary:
This thesis has resulted in a fabrication technique using bulk micromachining of silicon wafers to realize deep rectangular waveguide devices. This approach has the advantage of large-volume production, essential for commercial broadband wireless applications, and easier integration with other system components. This micromachining approach solves the problem of excess Ohmic losses, which can arise through the stacking of multiple wafer sections and from the final connection that closes the waveguide. In addition, a waveguide topology has been identified that allows bandpass filters to be fabricated without convex corners. This enables repeatable etching of the required wafer pieces, which is essential for filter applications. The micromachining technique has been refined through fabrication and careful characterization of three cavity resonators. The finalized procedure resulted in a cavity resonator with measured Q0's of over 4400 at both 30 GHz and 52 GHz. This is a ten-fold increase in the Q0 values of other alternate types of resonators at these frequencies, and compares very well with standard rectangular waveguide cavities.;An exploratory investigation of a unique growing evanescent wave resonant structure was also pursued. This consisted of a cutoff rectangular waveguide loaded by an inductive iris and a capacitive post. Theoretical and measured results verified the presence of a growing evanescent wave within the waveguide. Potential applications of this device are also discussed.;The micromachining process was also applied to the design of a bandpass filter with three topologies being considered: the length-stacked, height-stacked, and width-stacked designs. The width-stacked design offered the easiest fabrication as it did not contain any convex corners. A 3-pole, 30 GHz, 2.2% (0.667 GHz) bandwidth bandpass filter was designed and fabricated. The measured response resulted in a center frequency of 29.7 GHz, a bandwidth of 2.2% (0.654 GHz), and a deembedded passband insertion loss of -1 dB.
Keywords/Search Tags:Waveguide, Ghz, Resonators, Filter, Micromachining
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