Research And Design Of Ultra-Wideband Filter Based On Multi-mode Resonator

The rapid development of modern science and technology promote the people’s material and cultural living standards to be improved constantly. That also makes people have a more demand needs in the way and speed for getting information. Whether in the military or civilian level, this demand becomes more and more requirement as the continuous innovation and development of the technology. The ultra-wideband technology as a new communications technology, will be using for solving a major problem in the aspects of the transmission of information which in today’s or even future.As a key part of the ultra-wideband system, the Ultra-wideband filter located in the front of the RF system. Its key role is both to ensure that the system from interference band signal when receiving the signal, but also to limit a band of the transmitted signal in the system, so that ensure the signal’s quality, whether the system receiving or transmitting signal.After studied the knowledge about how to design UWB filter, this thesis based on multimode resonator(MMR) design an ultra-wideband filter. Since the FCC opened the frequency band between 3.1GHz to 10.6GHz to useful civilian for free, the researchers who study in ultra-wideband put their enthusiasm on this band. That lead to many kinds of structures of UWB filter which the band pass between 3.1 to 10.6GHz appeared. But there are few people to design the filter that high frequency above 11 GHz and base on the MMR structure. It is in this background, the thesis designed an ultra-wideband filter which band pass range of 4 to 12 GHz and produced it and tested. The following are the main components of this paper:1. Introduced the background and development of the UWB filter in today and future.2. Describes the relevant theory about microwave and filter area. Including transmission line theory, microwave network theory and some parameters of filter and its classification.3. Discussed the relevant knowledge of the resonator, and analyzed the features of the stepped impedance resonator(SIR). Finally, based on the SIR structure designed a low pass filter.4. Based on the MMR structure designed two ultra-wideband band pass filters In aid of computer software.5. Summary of this paper.