X-band GaAs Phase Driver MMIC optimized for GaN-based Phased-Array Radar Transmit Chain

In the transmit chain of high-power phased-array radars more and more use is made of Gallium-Nitride (GaN) high-power amplifiers (HPAs), while in the receive chain there is a trend to move to integrated silicon (Si) based components. The GaN amplifiers usually require a relatively high input power, making it necessary to include a medium power driver amplifier. For phased-array operation also a phase shifter in the transmit chain is required. In this paper the design and measurement results of an integrated phase-shifter-driver MMIC are presented, which has been optimized to directly drive an X- band GaN HPA. This Gallium-Arsenide (GaAs) MMIC has been designed to fit in a lowcost plastic QFN package to reduce the cost of the front-end module assembly. The realized QFN-packaged MMIC features a 6-bit digital phase shifter and a CW output power of more than 22 dBm at a source power of 5 dBm, from 8 to 11 GHz. Over this bandwidth the measured RMS phase error is less than 5 degrees.