A Broadband Voltage Variable Attenuator With High-Power Tolerance and Compact Size Based on Dual-Gate GaN HEMTs

Abstract

To achieve broadband and high-power tolerance voltage variable attenuator (VVA), this paper replaces the single-gate High Electron Mobility Transistor (HEMT) with a dual-gate HEMT based on the distributed stacked structure VVA proposed by Qorvo, which can effectively reduce the chip area and cost while ensuring the bandwidth and power tolerance. To verify the effectiveness of this method, a DC-30GHz single-gate HEMT structure VVA and a DC-30GHz dual-gate HEMT structure VVA were designed and implemented based on the 0.25μm GaN process, respectively. The experimental results show that compared with the single-gate HEMT VVA, the 0.1dB power compression point ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IP-0.1dB</i> ) of the dual-gate HEMT VVA increases by more than 8 dB, and the insertion loss decreases by 0.9dB, the dynamic range increases by 4dB, and the chip area is reduced by 27%. To the best of our knowledge, this is the first report of a VVA based on a dual-gate HEMT structure, which suggests that a multi-gate HEMT device is certainly a better choice for achieving a broadband VVA or switch with high power tolerance with limited chip area and cost.