High-Performance Wideband 0.25 μm GaAs pHEMT 6-Bit Digital Phase Shifter Design for C-Band Phased Array Applications

In this paper, a 6-bit digital phase shifter design is introduced for C-band phased array applications, which presents a high performance in a wide bandwidth between 4 GHz and 6 GHz. The design is performed using the process design kit for 0.25 μm Gallium Arsenide pHEMT applications by WinSemi foundry. For each bit, the optimal design topology is selected and revised with enhancements so that the phase shifter attains a phase shift response, high input/output return loss, and low insertion loss characteristics in a comparatively compact form. The step size for the digital phase shifter is 5.625° with a phase error of 2.8125° in each bit design, tracking the whole 360°. The overall input and output return losses are greater than 10 dB, and the insertion loss of the component is lower than 5.8 dB over the 4–6 GHz bandwidth. This successful performance is achieved within a chip area of only 2200 μm to 2200 μm. Embedded switch all-pass networks and switched high-pass/low-pass network topologies are employed and controlled in parallel within the design. Each bit topology, along with the element values, is optimized and validated for the best performance.