Innovative millimeter-wave components based on mixed substrate integrated dielectric-metallic waveguides

A major challenge facing the millimetre-wave and terahertz (THz) research fields, is the integration of different components in a compact, efficient and low-cost fashion. The concept of substrate integrated circuits (SICs) provides a vital alternative to traditional design by simplifying the integration of the rectangular waveguide (thus the SIW) with other planar transmission lines such as microstrip and CPW lines. While this has substantially enhanced the design techniques at the X- and K-band frequencies, limitations still persist at higher bands, especially the W-band and beyond. New implementations of the SICs concept using dielectric waveguides such as the substrate integrated non-radiative dielectric (SINRD) guide, were thus proposed and a number of SINRD-based circuits were designed at the W-band frequencies. Nonetheless, the SINRD guide has rigid design criteria that limit its practical use.;In this thesis, a modified version of the SINRD guide, based on the image NRD (iNRD) guide, is investigated. This work will be the first to investigate the feasibility of designing the iNRD guide with the SICs concept. The versatility of the resulting image SINRD (iSINRD) guide will be demonstrated by designing a number of passive components that operate at the W-band centre frequency of 94 GHz.;Specifically, the following contributions have been made at the W band frequencies of 88 GHz and 94 GHz: 1. An optimised design methodology of the NRD-class circuits. This method is a simpler alternative to earlier methods and is more informative. 2. A number of iSINRD guide transmission lines that are designed with different perforation profiles and with a different number of gaps in the metal wall. 3. Broadband and narrowband iSINRD guide sharp corners. 4. Two different configurations of iSINRD guide directional couplers that support dual mode (LSM10 and TE 20 modes) and dual band operation (one band for 0-dB coupling while the other for 3-dB coupling). The band pertinent to the 0-dB coupling is exclusive for one of the configurations. Thus, a total of six directional couplers are presented. 5. A cross-over structure that utilizes the dual band nature of one of the iSINRD directional coupler configurations is designed. In this structure, the LSM10 and TE 20 modes that are concurrently fed at the two input ports are collected at the opposite ports through the mechanism of 0-dB coupling. 6. A 180o iSINRD hybrid based on the LSM10 mode. 7. An asymmetric iSINRD-SIW coupler based on the LSM10 and TE01 modes. 8. A compact and simple orthogonal mode transducer (OMT), with the orthogonal modes being the LSM10 and the TE20 modes. 9. Even-odd mode analysis technique is used to construct a very compact iSINRD cruciform coupler. 10. An iSINRD magic-T circuits is developed by modifying the lengths of one of the arms of the iSINRD cruciform coupler. 11. Highlighting the advantages of the HFSS Eigen-mode solver.