Sub-mW Cryogenic InP HEMT LNA for Qubit Readout
Yin Zeng, J. Stenarson, Peter Sobis, Niklas Wadefalk, Jan Grahn
Abstract
The cryogenic indium phosphide (InP) high-electron-mobility transistor (HEMT) low-noise amplifier (LNA) is used for the readout amplification of qubits at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4$</tex-math> </inline-formula> K where cooling capabilities are limited implying that the dc power of the active circuits is an essential design constraint. In this article, the RF and noise performance of the InP HEMT under ultralow-power (ULP) operation at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4$</tex-math> </inline-formula> K has been characterized. The small-signal and noise parameter model of the InP HEMT was extracted down to 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula> W. The tradeoff between noise performance and dc power consumption was analyzed in terms of the drain current and drain voltage. A 4–6 GHz hybrid cryogenic HEMT LNA designed for qubit readout and optimized for lowest noise below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1$</tex-math> </inline-formula> mW dc power consumption was fabricated. The measured performance of the LNA at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4$</tex-math> </inline-formula> K attained 23.1 dB average gain and 2.0 K average noise temperature at 200 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula> W dc power.