A Ka-band 3-bit RF MEMS true-time-delay network

A monolithic Ka-band true-time-delay (TTD) switched-line network containing 12 metal-to-metal contact RF microelectromechanical system switches has been successfully fabricated and characterized on a 75-/spl mu/m-thick GaAs substrate. The compact 9.1-mm/sup 2/ TTD network was designed to produce flat delay time over a dc-to-40-GHz bandwidth with full 360/spl deg/ phase control at 45/spl deg/ intervals at 35 GHz. Measurements show a match to within 2% to the designed delay times at 35 GHz for all eight switch states with 2.2-dB average insertion loss over all states. Peak rms phase error is 2.28/spl deg/ and peak rms amplitude error is 0.28 dB from dc to 40 GHz. Return loss better than 15 dB from dc to 40 GHz for all eight states confirms the circuit's broad-band operation.