Design and Characterization of Microfabricated Three-Dimensional Millimeter-Wave Components

Date The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned discipline. Components Thesis directed by Prof. Zoya Popovi´c This thesis presents the analysis, design, and measurement of air-filled millimeter-wave rectangular coaxial components microfabricated on 150-mm silicon wafers. There is currently considerable interest in the application of new fabrication techniques for the implementation of classical microwave devices to improve performance while reducing size. In addition, the enabling of the design of novel, heretofore unrealizable devices is of interest. The air-filled transmission lines presented in this thesis have advantages over traditional planar transmission lines in that they are non dispersive, possess high isolation, are amenable to dense integration and sharp turn radii, are low loss for their cross section, and are much smaller than rectangular or circular metallic waveguides for a given frequency. As an example, a 50-Ω line with a 250 µm by 250 µm cross section has the first higher order mode starting at 450 GHz, the losses are 0.22 dB/cm at 26 GHz, and the isolation between two adjacent lines with a center-to-center separation of 300 µm is better than 60 dB/cm. In a multi-layer configuration, vias and crossovers with excellent broadband performance are quite naturally implemented. Millimeter-wave designs on both the component and subsystem levels are of interest. Air-filled, copper rectangular coax lines and devices with cross sections between 125 µm by 300 µm and 630 µm by 700 µm are fabricated by Rohm and Haas Electronic Materials LLC according to designs from this thesis. The research focus is the development of usable, high-quality millimeter-wave components which demonstrate the merits of this technology. Ka-band components have been designed, fabricated, and tested. Scaling in frequency has been investigated up to W-band, and the presently used fab-iv rication process could conceivably be used at frequencies into the hundreds of GHz. Connections to probe-based test equipment and standard circuit lines are designed. A method of de-embedding the probe structures of four-port data using the two-port TRL model is developed and shown to agree with simulations. Among other components, this thesis presents the design and comprehensive analysis of half-wave metallic cavity resonators fabricated using this technology. To the best of the author's knowledge, the measured quality factor of these resonators comes closer to the theoretical maximum than those …