Research And Design Of The Uwb Micro-strip Bandpass Filter

Filters as an important part of the communication system, play the important task of thesignal selection. Similarly ultra-wideband filter in the UWB system is a pivotal role, whichhas naturally become a hot issue for scholars. In the entire UWB frequency range, due to theexisting narrowband wireless communication signals, the wireless communication signalswould seriously interfere with UWB systems, such as the C-band and X-band used in satellitecommunications. To avoid mutual interference with existing communications, there is anurgent need to have the UWB band pass filter of flexible and adjustable notch characteristics.The UWB micro strip filter has been studied widely because of its simple structure andpracticable, such as multi-mode resonator (MMR) micro strip filters. Therefore, based on theMMR structure this paper is proposed to meet the actual needs of ultra-wideband filter andthe multi-pass band pass filter with adjustable notch.Firstly, the background and significance of the UWB filter is described, and the course ofdevelopment of the UWB filter and MMR is further summarized. on this basis the basictheory of designing UWB filter is outlined, such as the basic parameters of microwave filters,the knowledge of anglicizing microwave network and the design principles of classicalmicrowave filters.Secondly, the common design method for UWB filter is described, and after simplecomparison and analysis the MMR method is chosen. Through further detailed analysis of theMMR conditions and the specific design steps, combining the cross-finger resonant structure,and multi-mode resonator structure of square ring, achieving the filter bandwidthrequirements using the multi-mode resonator structure of square ring, changing the flow ofthe filter surface current using multi-mode square ring resonant structural, the ultra-widebandmicro strip filter with a good performance of high impedance is designed.Thirdly, through the transformation of the preceding UWB filter, a dual pass-band UWBfilter with tunable stop-band is designed using the open stub loaded. The influence that thefollowing structures bring is discussed: the uniform impedance resonators, the steppedimpedance resonators, three-stepped impedance resonators and the cone resonators. Thedual-pass band filters of flexible and adjustable notch characteristics. Finally, based on micro strip/coplanar waveguide structure the UWB filter formulti-notch is designed. Through the simulation and analysis of the ring resonator with thenested double C, using the characteristics of the multi-resonance point, the dual-pass bandfilters of adjustable stop band and the multi-band ultra-wideband filter of a single adjustablenotch are designed.