A novel low-cost beam-steering technique based on the extended-resonance power-dividing method
A novel phased array based on the extended-resonance power-dividing method has been presented. This method eliminates the need for separate power splitter and phase shifters in a conventional phased-array system, resulting in a substantial reduction in circuit complexity and cost. As a proof of principle, a 2-GHz extended-resonance-based phased array using varactor diodes and microstrip patch antennas has been designed, fabricated, and tested. The measured scan range is 20/spl deg/ and the measured efficiency of the extended-resonance phased-array feed is typically 80%, which corresponds to 1 dB of insertion loss.
Digital-type RF MEMS switched capacitors
This paper presents digital-type RF MEMS switched capacitors built in a coplanar waveguide (CPW) configuration. In this design, a MEMS shunt bridge is fabricated over an MIM capacitor. When the bridge is in the upstate position, the CPW line is loaded mainly by the up-state MEMS bridge capacitance. When the MEMS bridge is pulled down, the line is loaded by the MIM capacitor. As a result we obtain a digital-type switched capacitor suitable for 0.5-6 GHz operation. Switched capacitors of different values (300 fF, 600 fF, 750 fF, 1.5 pF, 2.25 pF) were fabricated and resulted in high-Q (>100) designs at 1 GHz. Also a 2-bit capacitor array was demonstrated. The values of Q are limited by metal-to-metal contact resistance (0.8 /spl Omega/) and the calibration accuracy of the method used.
Low cost Phased Arrays
Abstract : In a phased array antenna the phase shifters (or TIR modules in active aperture phased arrays) with their beam steering control circuitry along with the feed network, account for major hardware cost. This report examines a number of antenna array configurations that use simpler feeds, simpler phase shifting and beam steering control circuitry for realizing low cost phased arrays. Two lens configurations, one using diode strips (Radant) and another using voltage controlled ferroelectric dielectrics are identified to have high potential for low cost phased arrays. Ferroelectric dielectric lens may have further advantages of smaller thickness, simpler beam steering controls and lower costs.