Low-cost Microstrip-Based Ferrite Phase Shifter Utilizing Circular Polarization

The constantly increasing demand for low-cost electrically steered phased antenna arrays have resulted in a significant need for developing low-cost and high performance phase shifters. The ferrite phase shifter presented in this paper not only minimizes cost by using printed-circuit microstrip technology, but it also offers optimal performance in terms of insertion loss, return loss, and phase shift per unit length. By making various design changes to a previously presented design, including implementing ferrite with a magnetic saturation of 600 Gauss, using substrate materials of higher dielectric constant (9.8), designing all microstrip lines to be 50 Omega, and using quarter wave transformers at both the feed and termination ports, the phase shifter performance met and exceeded set specifications. Specifically, the insertion and return losses both at low and high bias regions were sufficiently and acceptably low, and the phase shifter provided over 360deg of total phase shift in about a wavelength. Higher values of insertion losses during the biasing range from 50 to 80 kA/m, which was observed in the simulation results and conformed experimentally, are still under investigation