Research And Design Of A Novel Microwave Ultra-wideband Bandpass Filter

UWB technology has become a new type of communication technology in wireless communication systems with its many advantages,and has played a key role in military and civilian fields.With the continuous advancement of UWB technology,UWB filters face many challenges such as higher selectivity and smaller size.The UWB operating band(3.1 to 10.6 GHz)is very wide,and it interferes with some narrowband communication systems,the development of UWB filters with notch bands has been further promoted.In view of the above research background,this paper has conducted in-depth research on UWB filters.The main research contents include:(1)A ultra-wideband filter with a notch band is proposed using novel multimode resonator The resonator is formed by loading T-shaped stub at the center of a classical half-wavelength uniform transmission line and loading two open stubs on both sides of the T-shaped stub.Based on this,an asymmetric coupling line is used to cross-couple with the resonator to realize an ultra-wideband filter,which can generate a notch band at 8 GHz.The filter flexibly controls the notch frequency by adjusting the length of the coupled line.The simulation results show that the filter can not only suppress the interference of signals in the X-band satellite communication system,but also has good in-band characteristics,small size and high frequency selectivity.Comprehensively considers the overall performance is excellent and conforms to the filter design standard.(2)A ultra-wideband filter with dual notch bands is proposed using open-circuit stubs.A three-mode resonator is obtained by loading the stepped impedance stub,and then two identical three-mode resonators are symmetrically distributed up and down to design a new multi-mode resonator.An input and output feeder are inserted at both ends of the new multimode resonator,and an ultra-wideband filter is realized by forming a cross coupling.A ultra-wideband filter with dual notched bands at 5.31 GHz and 8.1GHz is designed by loading two open-circuit stubs up and down at the input feeder end.After simulation and optimization,the results show that the filter has good performance,suppresses the interference of narrowband signals in wireless local area network(WLAN)and X-band satellite communication bands to UWB wireless communication systems,and solves the problems such as insufficient depth of the notch and weak resistance of notch band in previous UWB filter with notched bands.The paper has 53 pictures,6 tables,and 83 references.