Research On Filtering Function-Integrated Reconfigurable Microwave Passive Circuit

With the development of modern wireless communication system,miniaturization,low fabrication cost,and good performance are the important factors of microwave radio frequency circuit.To meet the high-integration demand of modern wireless communication system,the research of reconfigurable multifunctional circuits with filtering response has currently become a hot topic,where the multifunctional circuits not only reduce the fabrication cost,but also reduce the circuit sizes and mismatching losses introduced by the concatenations of multiple components.To solve the problem of poor performance of existent filtering function-integrated reconfigurable microwave passive circuits,an in-depth research and analysis and corresponding solutions are made in this dissertation.The main work of this dissertation can be summarized as follows:1.Reconfigurable filtering balun with simultaneous tunability of frequency and power division ratio:A filtering balun with simultaneous tunability of frequency and power division ratio is proposed by using the dual-mode resonator and open-circuited transmission line loaded with a varactor diode and a slide rheostate.With the varactor diodes and slide rheostate loaded onto the middle of the open-circuited transmission line,both the miniturization of the circuit sizes and the flexibly tuning the power division ratio at two ouput ports for filtering balun can be achieved.The tunable frequency of filtering balun can be obtained by tuning the varactor diodes loaded onto the dual-mode resonators.By constrast detection,the reconfigurable filtering balun proposed in this paper has the merits of miniaturized circuit size and the simultaneous tunability of frequency and power division ratio.2.Filtering balun-integrated lowpass-bandpass reconfigurable triplexer:By using the technique of distributed coupling and the method of series switch,multiple modules,including lowpass filter,filtering balun,switch,bandpass filter,etc,are effectively integrated into a single circuit.Initially,the lowpass filtering response of multiplexer can be controlled by tuning the voltages of switch.Subsequently,the bandpass filtering response of multiplexer can be controlled by tuning the voltages of P-I-N diodes loaded onto the multi-mode resonators.In addition,the opening and closure of filtering balun function are realized by tuning the voltages of P-I-N diodes loaded onto the dual-mode resonators.Eventually,multiple switchable operating states,which are lowpass-bandpasss triplexer,lowpass-bandpass diplexer,lowpass filter,bandpass filter,and filtering balun,etc,are firstly achieved in the proposed multifunction-integrated circuit by choosing different controlled voltages.3.Multi-mode reconfigurable two-way filtering power dividers:By choosing two different coupling topologies,two novel multi-mode reconfigurable two-way filtering power dividers are proposed.The first one is a triple-mode reconfigurable two-way filtering power divider.This power divider utilizes the resonance principle of P-I-N diodes-loaded dual-mode resonators,and a switchable filtering power divider with three operating modes is obtained by choosing different controlled voltages,where three modes are dual-band filtering power divider,high-frequency single-band filtering power divider,and low-frequency single-band filtering power divider.The second one is a dual-mode reconfigurable wideband two-way filtering power divider.This dual-mode power divider has two operating modes,i.e.,one wideband filtering power divider and one all stopband filter.According to the chosen coupling topology,a wideband filtering power divider with the simultaneous tunability of frequency,bandwidth,and power division ratio is firstly achieved based on a pair of varactor diodes-loaded tri-mode resonators and parallel coupled line technique.Initially,the tunable frequency and bandwidth of the wideband filtering power divider is obtained by tuning the varactor diodes loaded onto the resonators.Subsequently,the tunable power division ratio is realized by adjusting two varactor diodes loaded between the input parallel coupled lines.Eventually,one all stopband filter is achieved between two output ports by misaligning the resonant frequencies of two resonators and decreasing their couplings.4.Reconfigurable four-way filtering power dividers with tunability of frequency,bandwidth,and power division ratio:A reconfigurable four-way filtering power divider with simultaneously tunable frequency,bandwidth,and power division ratio is proposed by choosing the proper coupling scheme between the three-line parallel coupled line and stub-loaded quad-mode resonators.Initially,three kinds of switchable filtering responses,i.e.,wide/dual/single-band filtering response,can be realized in the wideband filtering power divider by tuning the varactor diodes loaded onto the quad-mode resonators.Subsequently,the tunable frequency and bandwidth of dual-band filtering power divider can be realized by tuning the varactor diodes loaded onto the resonators.Eventually,the tunable power division ratio can be obtained by tuning the varactor diodes loaded between the input parallel coupled lines.5.Reconfigurable dual-mode filtering power divider based on quasi lumped-element component:Based on the principle of high impedance transmission line equivalent to quasi lumped-element inductor and varactor diodes possessing tunable capacitance,a dual-mode multifunctional four-and eight-way filtering power dividers are proposed according to the chosen coupling scheme.Two operating modes are one frequency-agile filtering power divider and one all stopband filter.The tunable frequency of four-and eight-way filtering power divider is achieved by tuning the varactor diodes loaded onto the high impedance transmission line.One all stopband filter with high suppression between two nonadjacent ports is realized by misaligning the resonant frequencies of every resonator and decreasing the coupling between them.