Characteristic Analysis And Application Of The Localized Substrate Integrated Artificial Dielectric

As an important component, microwave circuits are widely used in systems of wireless communication, aerospace and navigation. Miniaturization, multi-functional and low-cost of microwave circuit has been attracting much attention of researchers. In2007, researchers proposed a new artificial dielectric to reduce the size of microwave circuit, which is called substrate integrated artificial dielectric (SIAD). In SIAD, there are metal posts embedded in substrate and those posts are shorted to the ground plane. As SIAD can increase the effective permittivity of substrate, it can effectively decrease the circuit size. This thesis mainly focuses on the characteristic analysis and application of SIAD. The main contributions of this paper are listed as below:1. This thesis explains the reason of miniaturization using SIAD. By comparing the characteristic impedance Zo of microstrip line on common substrate and SIAD, this paper proved that SIAD can increase the distributive capacitance and the effective permittivity, which results in the decreasing of microstirp circuit size.2. In order to ease fabrication and reduce cost, this thesis presents localized substrate integrated artificial dielectric (L-SIAD) structure, in which metal posts are right under the microstrip line. The transmission property of microstip line on L-SIAD is deeply researched by simulation and experiment with different values of post diameter, post height and post period.3. For the design of microstrip circuit on L-SIAD, this paper obtains CAD formulas for L-SIAD microstrip line through synthetic asymptotic technique. These formulas can be used for the calculation of the characteristic impedance Zo, propagation constant β and effective dielectric constantff of the L-SIAD microstrip line. Comparing with simulated and measured results, the average error of the formula is less than3%.4. The application of L-SIAD in the miniaturization of microstrip impedance transformer, power divider and hybrid coupler are researched in this thesis. The simulated and experimented results of those components are obtained. Comparing with ones on common substrate, the total area of those components reduce about50%.5. This thesis presents a new microstrip stepped-impedance resonator (SIR) with L-SIAD. The resonant frequencies and the electromagnetic bandgap (EBG) property of the SIR are discussed under different values of post diameter, post height and post period. To verify the practical application of the SIR, this paper designs a compact ultra-wideband (UWB) bandpass filter with it, and the experiment shows good bandpass response and wide upper stopband.6. This thesis presents a mushroom-like resonant cell (MRC) and designs an elliptic-function lowpass filter with the MRC. The simulated and measured results demonstrate that the filter has wonderful passband and wide upper stopband. Comparing with the example in reference, the size reducing of this filter in length and width direction is22.3%and59.2%, respectively.7. At last, the application of L-SIAD in the simplified dual complex right-left hand (SD-CRLH) is studied. This paper analyzes four equivalent circuit models of SD-CRLH with L-SIAD structure and these models can be used to design highpass, lowpass and bandpass filters.