4–20 GHz GaAs True-Time Delay Amplifier MMIC

A wideband amplifier with a fine control of the true-time delay (TTD) has been successfully implemented using a commercial 0.5-μm GaAs pHEMT monolithic microwave integrated circuit (MMIC) process. The proposed circuit effectively combines switching elements into an artificial transmission line structure in a distributed amplifier to achieve an adjustable TTD which enables time delay control with gain in a wider band than other GaAs-based TTD circuits. The TTD amplifier MMIC achieves a controllable delay of 9 ps, a gain of 9 to 2 dB, and a typical return loss of more than 10 dB from 4 to 20 GHz. The proposed TTD amplifier can be effectively integrated into a multifunction chip based on GaAs semiconductors for wideband active electronically scanned array or phased array systems.