A Millimeter-Wave Receiver Using a Wideband Low-Noise Amplifier With One-Port Coupled Resonator Loads

This article presents design techniques to facilitate the use of the driving point impedance (Z
₁₁
) of one-port transformer-coupled resonators as wideband loads of millimeter-wave amplifier stages for a 28-GHz receiver front end. While the use of both the Z
₁₁
of a one-port and the transimpedance (Z
₂₁
) of a two-port coupled resonator is considered to achieve a wideband response, it is shown that under conditions of low magnetic coupling and constrained network quality factor, the use of Z
₁₁
can result in a higher gain-bandwidth product of low-noise amplifier (LNA) amplifier stages. The effect of the complex zero in the Z
₁₁
response on the in-band gain ripple is shown to be alleviated merely by lowering the quality factor of the transformer's secondary coil; this strongly motivates the use of compact, nested-inductor transformer layouts. Implemented in a 65-nm CMOS process, a three-stage LNA (with Z
₁₁
wideband loads in two stages) achieves a 24.4-32.3-GHz bandwidth (27.9 % fractional bandwidth), a peak S
₂₁
of 24.4 dB (20.4 dB), a minimum noise figure (NF) of 4 dB (4.6 dB), and an input-referred P1dB of -23 dBm (-22 dBm) while consuming 22-mW (9.9 mW) power from a 1.1-V (0.85 V) supply. The use of compact transformers limits the LNA's footprint to only 0.12 mm2. A 26.5-32.5-GHz quadrature receiver prototype employing the LNA achieves a 29.5-dB peak conversion gain, a 5.3-dB minimum NF, and a -26-dBm inputreferred P1dB while consuming 33 mW from a 1.1-V supply.