Investigation On SIW Parameter Extraction Method And SIW Passive Components

Substrate integrated waveguide(SIW)is generally regarded as a new kind of transmission line.Classical metallic waveguide components have excellent performance as well known nowadays,but bulk size and heavy weight limit their applications in the design of planar integrated circuits.Components designed on SIW technology can maintain advantages of waveguide components,such as,high quality factor,high power capacity and good performance in EMI and EMC.Simultaneously,SIW technology has inherited many advantages of conventional planar circuits,including low cost,compact size,easy fabrication and high integration flexibility with other planar circuits and so on.Therefore,microwave and millimeter-wave components based on SIW technology are hot research topics in recent years.In this dissertation,a numerical short-open calibration(SOC)method is presented to numerically de-embed the complex propagation constant of a SIW or a HMSIW.Examples using the SOC method are given to validate its accuracy.Simultaneously,several SIW components which may be used in microwave and millimeter-wave integrated circuits and systems are designed.The main contributions of this dissertation are summarized in the following:(1)A numerical short-open calibration(SOC)method is presented to numerically de-embed the complex propagation constant of half mode substrate integrated waveguide.The numerical stability and convergence are illustrated.(2)Three examples designed with the application of our SOC method are given.Firstly,the propagation characteristics of SIW versus some key parameters are analyzed and discussed with SOC method;Secondly,a HMSIW leaky wave antenna is designed and its radiation pattern is calculated from the de-embedded complex propagation constant with SOC method;Lastly,the corrugated substrate integrated waveguide(CSIW)with no metallic vias is proposed and its propagation characteristics are investigated via our numerical SOC de-embedding method.(3)A novel Coplanar Waveguide(CPW)to SIW transition is presented.The new structure integrates the classical current probe transition with asymmetrical stepped impedance transformer to improve the operating bandwidth.Its equivalent circuit model is also given.(4)A simplified ray tracing method is used to approximately predict the coupling characteristics of H-plane multi-aperture SIW couplers.The output power of the output ports are calculated with the reflection and the transmission coefficients at the coupling windows.The ray tracing method provides a simple and efficient way to determine the initial values for the geometrical parameters of SIW-based multi-aperture couplers.From these initial values,the structures of the couplers can be quickly optimized with less iterations and the design efficiency can be greatly improved.In order to get high isolation,a criterion is introduced to prevent exciting higher-order propagating Floquet modes in the SIWs.Four examples of multi-aperture couplers are designed with our approach.(5)We propose a novel microwave attenuator based on multilayered substrate integrated waveguide(SIW).The relative dielectric constant and loss tangent of FR-4 at high frequencies are at first experimentally extracted by testing a fabricated ring resonator on FR-4 substrate.An equivalent circuit of this single unit structure is developed to theoretically predict the propagation characteristics of the designed attenuator in an efficient and effective manner.And,an example of SIW-based attenuator is given.(6)A novel approach is proposed to design triple-mode SIW filters.Two degenerate modes of a SIW rectangular cavity and the resonant mode of a complementary split ring resonator(CSRR)are employed to implement these filters.The primary advantage of using the CSRR-mode instead of the fundamental mode of the SIW cavity is that the frequency band of designed SIW filters can be controlled by changing the external dimensions of CSRR.Three examples of SIW multi-mode filters are given to verify the effectiveness of the method.