Miniaturization Miniaturization Of The Microstrip Resonator Filter Design,

As the rapid development of wireless communication technology, the miniaturization of electronic equipment becomes a very significant problem. In RF / Microwave front-end circuits, with the development of semiconductor integrated circuit (IC), the miniaturization of the active circuit units such as amplifiers and oscillators have made an enormous breakthrough. But in the field of passive circuits, especially filters and antennas, miniaturization is still an unresolved problem. Recently, the miniaturized and high performance microwave filter researches become a hot issue in the relevant research areas.Firstly, resonators'miniaturization technologies were studied in this thesis. The resonance conditions of chip resonator, ring resonator, hairpin resonator and SIR (Stepped-Impedance Resonators) resonator were theoretically analyzed respectively. According to the elaborate theory analyzing, general ideas of resonator miniaturization were proposed. On the basis of the general ideas, four filter miniaturization methods were summarized by studying the domestic and overseas relevant miniaturized design examples.Secondly, the polygonal open-loop resonator was studied. Combining with several miniaturization technologies, such as loop-folding, SIR, capacitive loading, slow-wave structure loading, grooved microstrip lines and so on, a miniaturized hexagonal open-loop resonator and a novel octagonal open-loop resonator were proposed. By electric field coupling, three second-order bandpass filters with elliptic function response and high miniaturization performance were design and fabricated. The measurements of these filters were agreement with designed values.Thirdly, dual-mode filter miniaturization designs with LTCC (Low Temperature Co-fired Ceramic) multi-layer structure were studied in this thesis. The miniaturization principle of dual-mode resonator with capacitive loading was analyzed by odd-even mode analyzing theories. Using the LTCC technology, broad-brimmed coupling structure, dual-mode resonator unit and lumped capacitances were designed and simulated respectively. Then, after combining the three separate designed elements, a capacitive-loaded dual-mode filter was designed by four layers LTCC structure. The simulation results show that the dual-mode LTCC filter has prominent stop-band spurious suppression ability and the plane area of this filter reduces more than 35% compared with the unloading dual-mode filter.Finally, the longitudinal expansion thought of high-order cascade filter design was presented. In order to verify the realization possibility, a four-order vertical cascade dual-mode filter was design using seven layers LTCC structure. The designed filter not only has good filter response, but also has 50% miniaturization capability compared with the plane four-order dual-mode filter.