Research On Negative Group Delay Circuit And Filter Power Divider Circuit

As one of the important components of the communication system,the performance of microwave passive devices is very important to maintain the integrity of the whole signal of the system.In this paper,negative group delay circuit and filter power divider are studied.The specific work is as follows:1.A resonance-type self-matching NGD circuit based on grounded coplanar waveguide line is proposed.The circuit structure generates NGD phenomenon by resonance in parallel of main transmission line,resistance and coupling line.Using the odd-even mode method,its working principle are expounded,odd-even mode equivalent model is set up according to the principle of the transmission line impedance,continue to network transmission parameters of circuit components are derived expressions that intuitive reveals the circuit parameters on the characteristics of NGD each part,simplify the design process.Then,the working mechanism of the circuit is verified by simulation analysis,and the resistance value is adjusted to make the circuit reach the matching state.The center frequency of the NGD circuit can be effectively controlled by adjusting the electric length of the coupling line.Compared with other resonant NGD circuits,this structure can achieve good passband matching and has less insertion loss.2.The principle of phase difference caused by distributed parallel interconnect transmission designed a low insertion loss NGD circuit based on the structure of suspension line,from the innovative exploration on the forming principle and structure design,network parameters is analyzed using the transfer matrix method to reveal the physical mechanism,by using pure distributed circuit design,as compared to other forms of NGD circuit without resistance,reduce the circuit loss at the same time,simplify the design process,in addition,due to the structure of the suspension line grounding method are surrounded by the surface,make the encapsulation based on the design of the circuit produces features,this feature effectively reduces the radiation loss of the circuit,Reduce the insertion loss during signal transmission.3.A filtering power divider based on grounded coplanar waveguide is proposed.The resonance characteristics of the step impedance and coupling line hybrid structure resonator are analyzed by odd-even mode analysis combined with full-wave simulation,and four odd-even mode resonant frequency points are shown.Based on the resonator and coupled line terminal load step impedance(SIR)line,a wideband bandpass frequency response is constructed and three bandpass filters with zero transmission points are formed outside the band.This band-pass filter is fused with the Wilkinson power splitter,and the matching design should be paid attention to when the two impedance transforms are replaced,and the isolation resistance is bonded to the SIR opening end of the two lines to realize the isolation between the output ports.The introduction of SIR resonator makes it possible to form three transmission zeros outside the filter power splitter band.Based on the above principle,design a broadband filter,power splitters,the filter has a lower insertion loss,good,restraint outside the band and two output port has good isolation degree,with the advantages of flat group delay value,compared with other forms of filtering power splitters,the designed structure has the obvious advantages of superior performance and compact size.