| With the rapid development of wireless communication technology,the size miniaturization of electronic equipment has come to the fore,and multifunctional integrated devices came into being.Among them,the most widely used is the integration of filter and microwave passive components such as coupler,power divider and phase shifter.Filter and phase shifter are widely used in microwave systems such as phased array antenna and antenna feed network,which plays a major role in the performance of RF communication system.Therefore,based on the theory of microwave technology and the comprehensive analysis method of filtering phase shifter,this thesis studies and designs several types of filtering phase shifter from the aspects of broadband and dualband performance,which are briefly summarized as follows:1.The filtering phase shifter with broadband performance is researched and designed.Firstly,a low-pass/all-pass filter phase shifter based on lumped element is designed.Starting from the ABCD matrix of the structure,the principle of filtering and phase shift is explained by using the microwave theory.The relationship between the phase shift value,frequency and unknown parameters is obtained,and then the values of capacitance and inductance in the topology are determined.It has the advantages of simple structure and wide working bandwidth.Then,two broadband filtering phase shifters based on microstrip line structure are designed.A broadband filtering phase shifter based on π-network is designed by taking advantage of the low insertion loss of π-network elements.The structure has the advantages of wide phase shift range and wide working bandwidth,and realizes the phase shift of 45° ～ 270°.In addition,a broadband filtering phase shifter based on C-type coupling line is optimized.Compared with the traditional π type network unit,the improved structure unit has advantages in bandwidth performance.Finally,the90° phase shifter is simulated and tested.The experimental results show that in the bandwidth range of 0.9 GHz ～ 3.36 GHz,the insertion loss of the filter phase shifter is less than 0.7 d B and the phase imbalance is 5°.Compared with the previous structure,the filtering phase shifter has the advantages of simple design,wide phase shift range,small phase deviation,small insertion loss and wide working bandwidth ratio.2.A microstrip filtering phase shifter with completely independent dual passband is designed.The structure uses the phase shift characteristics of Schiffman unit and cascades it with traditional filter unit.Starting from the filtering performance,the equivalent model of the filter unit is obtained by using the comprehensive analysis method of the filter,and the relationship between the impedance value of the element and the electrical length is obtained by using the resonant characteristics of the filter unit;Starting from the phaseshifting performance,the contribution of filter unit and Schiffman phase-shifting unit to phase-shifting response is analyzed.Then,the influence of the performance index of the filtering phase shifter（including double passband center frequency ratio,absolute bandwidth ratio and phase shift value ratio）on the impedance value and electrical length of each element is analyzed.Finally,the 90°/270° filtering phase shifter is simulated and measured.The experimental results show that the working bandwidth is 150 MHz/120 MHz,the double passband insertion loss is less than 3.3 d B/3.4 d B,and the phase imbalance is 5°.Compared with the previous structures,the filtering phase shifter designed in this chapter can realize the performance of dual-band filtering phase shift,and has the advantage that the performance of dual-band（including filtering performance and phase shift performance）can be adjusted independently. |
