Substrate Integrated Theoretical Analysis And Application Of The Ridge Waveguide

With the rapid development of wireless communication, some critical requirements on the microwave devices are arousing, such as low profile, wide band, high reliability, miniaturization and high integration etc. Based on the mature development of SIW theory and engineering, an innovative structure named ridged substrate-integrated waveguide (RSIW) is proposed in this thesis, which aims at the bandwidth enhancement over previous SIW structure.The characteristics of propagation, cutoff and bandwidth of RSIW are thoroughly investigated in this thesis. The formulas of propagation and cutoff frequency for TE₁₀ mode are firstly derived, as well as the formulas of cutoff frequency for higher modes in RSIW. Good agreement between calculation and HFSS-based simulation verify the validity of the derived formulas. The theoretical and numerical results both indicate about 40% bandwidth enhancement over SIW by RSIW. To further enhance the bandwidth of RSIW, one novel technique is proposed, in which some metal strips are added at the other ends of the central ridge posts. The formulas for the propagation and cutoff characteristics are also derived, the results show over 120% enhancement in the terms of bandwidth. These formulas are expected to provide effective guidance for the engineering application of RSIW.To implement the connection of RSIW and planar circuits, novel transition between microstrip line and RSIW has been designed; the measurement of the prototype verifies the validity of the design strategies. With such advantages like compact structure and broade bandwidth, RSIW will be found wide applications potentially in some wideband microwave devices and subsystems.