Reconfigurable SIW Phase Shifter Based on Parallel Stubs Loaded With Surface Mount p-i-n Diodes

This letter proposes a robust approach for developing a new class of electrically reconfigurable phase shifter. This design employs via posts on substrate integrated waveguide (SIW) technology in conjunction with surface mount p-i-n diodes. To ensure optimal performance over the intended frequency band in a space-efficient manner, the transmission line is based on an SIW, which offers superior low-loss properties. In addition, p-i-n diodes are integrated into the SIW line using transverse coplanar waveguide (CPW) stubs. The efficiency of the proposed design method and the practicality of incorporating an innovative biasing circuit on a single layer without requiring additional wire bonding layers are demonstrated in the experimental prototypes outlined in this letter. This approach facilitates a scalable and modular device design. The principle of achieving such high-quality circuits is detailed and is also confirmed by experimental and theoretical results, which are in good agreement up to at least 6 GHz, validating the design procedure and demonstrating that complex circuit functions can be achieved with relatively inexpensive compact structures. The proposed structure has potential applications in time-varying systems, communication receiving sections, and beamforming networks.