InAlAs/InGaAs HEMT control circuits are studied for monolithic InP applications. Experimental characteristics are presented for bridged-, T- and π-topologies. Best performance is obtained for single-cell π-attenuators. (DC to 26.5 GHz with 30 dB dynamic range and -19 dB return loss). These excellent broadband characteristics benefit from the high electron mobility of the devices. Less than 1 nsec switching times were measured. Small-signal characteristics of the π-attenuator were maintained up to input-powers of about 11 dBm at 5 GHz. The technology merits and suitability for very high frequency applications are discussed.
