High-Power RF-MEMS Phase Shifters for Phased-Array Applications

Active phased array radars are expensive and solid state power and low noise amplifiers are a major component of that expense. Sharing these amplifiers amongst many antenna elements is a strategy for reducing expense. However, in order to maintain independent phase control, the phase shifter and its attendant insertion loss must then be inserted between the amplifier and the aperture instead of being positioned behind the amplifiers. The phase shifter RF insertion loss then adds to the receiver noise figure and subtracts from the transmitter output which requires the phase shifter to have very low insertion loss (100 billion cycles) compatible with military requirements and RF power handling capacity (10 W) accommodating of many transmitter outputs. It is now possible to integrate these switches on a single substrate along with phase delay and advance networks to create an integrated phase shifter with the required performance parameters.