Investigation On Microwave And Millimeter Wave Substrate Integrated Filters

Filter is one of the key components for the microwave and millimeter-wave wireless systems. It is of practical importance to design filters with high integration, high performance, and miniaturized size. Based on Substrate Integrated Waveguide (SIW) technology and Printed Circuit Board (PCB) process, this dissertation has investigated and designed the miniaturized SIW bandpass filter with capacitive loading, single-cavity dual-mode SIW filter with non-resonating node, asymmetric response filters using the controllable electric and magnetic mixed coupling. Experimental study and discussions on each research topic was also carried out to verify the design methodology. The dissertation is organized as follows:This introduction briefly reviews the background of the related field at first. And then, the current study situation on SIW is introduced. Next, the main contents of the dissertation are elaborated.Chapter two studies the characteristics and principles of the capacitive loaded SIW cavity resonator. The area of the capacitive loaded SIW cavity can be reduced to about20%of the one without loading with the same dominant mode. A miniaturized two-pole chebyshev filter has been designed with the capacitive loaded SIW cavities using PCB process, along with its SIW counterpart for comparison. Measured results are good agree with the full-wave simulated ones.Chapter three proposes a new structure of NRN for the dual-mode SIW cavity resonator filter using two-layer PCB process. A new transmission zero can be achieved with the existence of the coupling between the NRN and the resonant mode, than a better frequency response can be obtained for a sing-cavity dual-mode SIW filter with a similar area. The proposed filter with NRN shows the advantage of good selectivity and easy integration with other planar circuits.Chapter four proposes a type of SIW filter with asymmetric frequency response using a controllable mixed electric and magnetic coupling. The filtering characteristics can be adjusted by allocating the transmission zeros, and the principles have been analyzed. This kind of filter can be further used to design duplexers with high performances.