Design of a 0.15-2 GHz high-resolution vector-sum broadband phase shifter with controlled programmable attenuators for stochastic cooling system

In this paper, a new 0.15-2 GHz broadband phase shifter with 9-bit phase resolution is presented. This broadband digital adjustable phase shifter is implemented by utilizing the signal vector summation technology. The phase shifter consists of one 90(degrees) hybrid coupler, two digital attenuators, two 180(degrees )hybrid couplers, two microwave switches, and one combiner. By adjusting the attenuation value of the two digital attenuators, the device creates a minimum 0.7(degrees )stepped phase shift. In addition, by switching the two microwave switches, a 360(degrees) range of phase shift is achieved while almost keeping the amplitude of the phase shifter constant. The measurement results show that the proposed phase shifter achieves a phase resolution of 0.7(degrees) while exhibiting an average insertion loss of 9 +/- 2 dB and phase unbalance within +/- 10(degrees). The calculated RMS phase error of the broadband phase shifter is below 5(degrees) from 0.15 to 2 GHz.