Abstract:

In order to modulate the phase shift of RF signal generated in the process of transmission, a reflection-type 360° analog phase shifter operating at 4.0 GHz is designed. It uses a branch-line coupler and two varactor-diode circuits to achieve 360° phase shift. It uses a three-branch branch-line coupler instead of a two-branch branch-line couple
r to increase the bandwidth. And a new reflective load is used to get more freedom of adjustment of the linearity and bandwidth. The results of simulation and measurement on the linearity and insertion loss are presented. The results show that the design has a 360° phase shift range and a 200 MHz bandwidth with a 15° phase shift error and a 3.5 dB insertion loss at the center frequency of 4.0 GHz.

Key words: wideband coupler, phase shifter, reflection-type, varactor diode, linearity