Planar type liquid crystal phase shifter based on the microstripline structure

Novel conversion circuit, which connects normal microstripline (MSL) and inverted-MSL (I-MSL) structure, is designed to attain planar type liquid crystal (LC) phase shifter based on the MSL structure. The new circuit enables us to introduce a thin LC layer easily on the MSL substrate by using normal sandwich cell structure. Here, fundamental phase shift properties are estimated, and then the conversion circuit, which is the key part of the device, is optimized to improve the device performance.