Design Of Multilayer Structure Filter For Wireless Communication System

The implementation of bandpass filter using the multilayer structure of microstrip resonator and the implementation of multi-layer bandpass filter which based on the substrate integrated waveguide (SIW) technology was presented in this thesis. Besides, the SIW-microstrip transition and the SIW–CPW-microstrip transition have been designed to integrate the SIW components with other microstrip circuits or measure the SIW components expediently.Theoretical analysis has been presented for the open-loop resonator structure. And the electric coupling, magnetic coupling and mixed coupling characteristics of the open-loop resonator are investigated. Furthermore, multi-layer structure can be used to design Chebyshev, Elliptic function bandpass filter and so on. And this thesis presents the fourth-order Chebyshev bandpass filter and the four Poles Quasi-Elliptic bandpass Filter. By comparison, size reduction of about 50% can be achieved by using the multi-layer structure.Based on the square and circular SIW resonator, two-cavity cascaded single-layer band-pass filter, two-cavity coupled double-layer bandpass filter, three-cavity coupled three-layer bandpass filter, four-cavity coupled four-layer bandpass filter, and four-cavity coupled double-layer bandpass filter have been designed. By analyzing the results of these filters, it found that the performance of the multi-layer SIW bandpass filter is the same or a litter better than the corresponding single-layer SIW bandpass filter. But the multi-layer structure can meet the smaller size requirements of wireless communications system.