Research Of High Power Capacity Phase Shifter With Low Insertion Loss

Phase shifters are common components in microwave and millimeter wave technology field. They are widely used in radar systems, communication systems, electronic warfare systems and so on, especially in phased array systems. The performance of the phase shifters have a significant effect on all these systems. Their tiny size, low insertion loss, high power capacities and stability for modern aerospace application are major design concerns. Based on conventional loaded-line phase shifters, a modified structure is introduced in this dissertation. Different from conventional loaded-line phase shifters, the new ones can achieve phase shifts using single-pole single-throw switches (SPSTs) to adjust the length of the stubs. As a result, error once due to via hole will be reduced, and the structure is easily fabricated. Furthermore, SPSTs are positioned on the open stubs. Meanwhile, due to the fact that electric current through these switches are only a fraction of those through the entire phase shifter, the power capacity of the phase shifter can be improved.PIN diodes and FET diodes are often used as switches in phase shifters. Compared to FET diode phase shifters, PIN diode phase shifters have lower insertion loss and higher ratio of performance to cost. Here, PIN diodes are chosen as switches in designing X band 5-bit phase shifter. In the design of the first edition, simulation and experimental results don't agree very well. Then, the effect of the PIN diodes on the phase shifter is analyzed and compensated. Finally, with the compensation method of the PIN diodes employed, the modified edition of X band 5-bit phase shifter is designed, fabricated and tested. Simulation and experimental results are in good accordance. The measured insertion loss of the phase shifting module is less than 3.5 dB from 9.4 to 10.5 GHz for all the basic phase shift states, superior to its counterparts. So the phase shifting module has good application prospect. To reduce the size of the proposed phase shifter, a multi-phase phase shifter structure is designed. It can achieve two independent phase shift states on a single phase shifter element.