A novel scheme for microwave substrate integrated waveguide circuit integration and miniaturization using lumped elements is studied. This dissertation proposes three approaches to expand the substrate integrated waveguide circuit integration concept.
Substrate integrated waveguide-to-planar transmission line transitions using lumped inductors and capacitors are introduced and developed. Their applications, substrate integrated waveguide quadrature power divider, balun, and amplifiers are also researched. The proposed transitions between substrate integrated waveguide and planar transmission lines show miniaturized transition structure, and proves the integration method through the new applications. Most of the proposed transition schemes yield approximately 0.8 dB ± 0.5 dB pass-band insertion losses per target band. Others such as SIW quadrature power splitter works with 4 dB ± 0.5 dB insertion loss per band of 4.2-5.5 GHz, 90° ± 5° phase variation per 4.49 to 5.9 GHz, and SIW balun works with 4 dB ± 0.5 dB insertion loss in 4.34-5.29 GHz, 180° ± 5° phase variation in 4.6-5.34 GHz. The prototype of proposed SIW amplifier demonstrates a gain of 15dB with 3 dB bandwidth of 4 GHz to 7.05 GHz.
Substrate integrated waveguide attenuators using lumped resistors are suggested, which prove a new possibility to expand the substrate integrated waveguide applications. A resistive π network was structured using standard surface-mounted resistors to obtain appropriated attenuation levels. The proposed SIW attenuator features the measured attenuation levels (1, 3, 5 dB) across 8.04 to 11.12 GHz. In half-mode substrate integrated waveguide attenuator, the five attenuators (1 to 5 dB, 1 dB step) are evaluated in a broadband frequency range of 7.29 to 14.9 GHz.
Novel half-mode substrate integrated waveguide balun and quadrature power divider based on composite right and left-handed structure using lumped inductors and capacitors are proposed and developed to miniaturize the SIW circuit and obtain broadband characteristic. The measured prototype of proposed half-mode substrate integrated balun shows a 1 dB amplitude imbalance and ± 5° phase difference in a frequency band of 8-13.3 GHz, 50% bandwidth. In proposed quadrature power divider, the measured amplitude, the phase difference and isolation between two output ports of the proposed structure have 1 dB, ±5° and under -15 dB in a wide frequency range of 4.1-6.68 GHz, 47.9% bandwidth, respectively.
All of the components were simulated and measured to prove their excellent performances, miniaturization and integration throughout this dissertation.