| With the rapid development of modern mobile communication technology, the size of mobile communication systems is getting smaller and smaller, which puts forward higher requirements for the mobile communication system devices, such as filters. So, the components with smaller size should be not only well in performance and frequency selectivity, but also low in insertion loss. In the microwave, to study the miniaturization, high-performance microwave filters has become a hot topic for the insufficiency of miniaturization of oscillators and microwave filters, especially the bottleneck of the miniaturization of microwave circuits in the miniaturization of the passive circuits.Firstly, basic theories of microwave filters and the performance indicators are summarized. According to the comprehensive theory of the coupling matrix, coupling coefficient matrix can be achieved through the coupling matrix rotation zero suppression. Secondly, basic characteristics of the dielectric filter and the extraction process of the coupling parameters are described. After simulating the cylindrical dielectric resonator and square dielectric resonator by using the CST software, the split and coupling of the degenerate modes in the case of screw coupling and slotted coupling are analyzed, which can be used to design the 2-order dual-mode dielectric filters. Finally, a new type of coupling structure of the 4-order dielectric filter is given, and the coupling design between the cavities is analyzed. Then, simulations for the designed filters show the correctness of proposed theories and techniques. |
