Dual Media Filter

In recent years, along with the high development of wireless communication in business, the miniaturization of electron equipment becomes a very important problem. Almost all intermediate frequency and base band in lower frequency circuits, adopt large-scale integrate circuit include filter, so the miniaturization of these circuits upgrades along with the development of semiconductor. In aspect of microwave, along with the development of single chip microwave integrate circuit, microwave active circuits, such as amplifier, modem, become more and more miniaturized, but there are deficiency in microwave filter and oscillators' miniaturization, especially the miniaturization of microwave passive circuits becomes a bottleneck in microwave circuits' miniaturization. So, developing high performance and miniaturized microwave filter is a hot topic in nowadays.In this thesis, the main research contents are the principles and applications of the dielectric dual mode filter. First, the basic theory on the microwave filter, and the basic operation theories for therectangular and cylinderical dielectric resonator are introduced, then researched the field distributions,modes resonant and quality factor of the dielectric resonator by using the open waveguide model. Thethesis also introduced the microwave material applied on dielectric resonator and it's characteristic. Then, the split and coupling of the degenerate modes are analysised by using the equivalent doubly tuned resonant circuit. Based on these theories, we use the HFSS software to simulate the split and coupling of the orthogonal modes of the rectangular dielectric, and two new coupling structures are put forth, which have better result verified by simulations. At last, the modes of the cylinderical dielectric resonator loaded cavity are researched and two dual-mode filters are designed. Based on the analysis of the modes, a new structure coupling three hybrid modes is given, and a three modes filter with one cavity is designed.