A 1.5–45-GHz High-Power 2-D Distributed Voltage-Controlled Attenuator

Abstract

We present the development of an ultra-wideband and 1-W voltage-controlled attenuator (VCA) using a 0.15- $\mu \text{m}$ enhancement mode gallium arsenide pseudomorphic high-electron mobility transistor technology. For the first time, a 2-D stacked field-effect transistor configuration is employed in a distributed VCA to simultaneously achieve wide bandwidth, high power, high dynamic range, and low insertion loss. The systematic design methodology is proposed, and a VCA prototype is fabricated and measured for verification. The monolithic microwave integrated circuit (MMIC) VCA exhibits a measured insertion loss of 1.9–5.5 dB from 1.5–45 GHz. The measured highest input 1-dB power compression point ( $P_{\mathrm {1dB}}$ ) is 30 dBm with a dynamic range of 26 dB. To the best of the authors’ knowledge, this paper reports the highest bandwidth and $P_{\mathrm {1dB}}$ of a single MMIC VCA while still maintaining excellent performance regarding dynamic range, insertion loss, and chip size.