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 corners4. Two different configurations of iSINRD guide directional couplers that support dual mode (LSM10 and TE20 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.