Design And Realization Of Mixed Coupling Filters Based On SIR

Filter is the key device to the radio technology system, and its performance directly affects the performance of the whole system. Due to the rapid development of the wireless communication systems and portable, the filter has to develop towards the direction of high performance, miniaturization and low cost.This paper put forward a series of new step impedance resonator(SIR). They have the compact structures and they are all easy to integrate and the harmonics of these resonators are adjustable. The filters using the resonators and the electromagnetic coupling technology can introduce multiply transmission zeros. In this way, the out of band rejection can be enhanced. These filters have the performance of compact size, high selectivity and zero adjustable.Firstly, in this paper, the basic index of the filter, the basic function, the meaning of electromagnetic coupling and the electromagnetic coupling filter function is illuminated in detail.Secondly, the traditional λ/4 SIR and the second order filter which is composed of SIRs are analyzed in detail. Then a fourth order wideband filter is designed with using the SIR structure and electromagnetic technology. The novel ring SIR structure is analysed in detail. The second,third and four order filters are designed based on ring SIR, and another third order filter is designed composed of a short-circuit built-in ring SIR and two traditional SIRs. Then the structure of the traditional SIR is improved forming the structure of the sector SIR structure. A fourth-order circular single pass band filter is designed with sector SIR.Finally, the stub loading SIR which is based on the traditional λ/4 SIR structure is analysed detailedly. Using the resonators with electromagnetic coupling technology, a double bandpass filter is designed. Another filter is designed with electromagnetic coupling technology and using ring SIR replacing of the traditional SIR in the stub loading SIR. Then the stub loading SIR’s stub built-in, using electromagnetic coupling technology combined with the Defected Ground Structure(DGS) or joining the source load coupling two double bandpass filters are designed. A class of double bandpass filter is designed which is compose of the ring SIR resonators and traditional SIR resonators with electromagnetic coupling technology. The above-mentioned double bandpass filters are all import multiple TZs which improve the option characteristic of the filters.