Development of passive components for millimeter-wave circuits.

Abstract

In this thesis, two novel transmission lines, Layered Ridge Dielectric Waveguide (LRDW) and Finite Ground Coplanar (FGC) waveguide, are developed for millimeter-wave integrated circuits. The Effective Dielectric Constant (EDC) method is used to develop a set of design equations and figures that can be used to optimize the power confinement and dispersion characteristics of LRDW. These guidelines are used to illustrate the design of a 110 GHz waveguide, and by using this design, the limitations that standard IC fabrication processes impose upon the waveguide are discussed. Measured propagation characteristics of LRDW at Ka-band are presented where it is seen that the waveguide has very low attenuation. Furthermore, it is shown that the propagation characteristics predicted by the EDC analysis agrees with the measured results. The design of a novel transition from rectangular waveguide to LRDW is presented that has a measured return loss better than 16 dB and an insertion loss of 2.0 and 0.5 dB at 26.5 and 40 GHz respectively. General design equations are presented that can be used to design transitions between rectangular waveguide and the general class of ground plane supported dielectric waveguides. Lastly, the development of leaky wave antennas that consist of a periodic array of metallic strips on top of the LRDW is presented. Measurements show that the main beam of this antenna scans with frequency at the rate of 8.1 degree/GHz. Finite Ground Coplanar waveguide is investigated to determine the minimum ground plane width that still maintains low attenuation and dispersion. It is shown that the ground plane width can be made as small as twice the center conductor width without degrading the transmission lines performance. The integration of passive components in the ground planes of FGC is also investigated. These results show that the ground planes can be used in the same way as the center conductor of norm coplanar waveguide, and elements placed in the ground planes appear as two elements in parallel. Thus, by using the ground planes and the center conductor of FGC, novel circuit layouts are possible.