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 (Z₁₁) 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 Z₁₁ of a one-port and the transimpedance (Z₂₁) 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 Z₁₁ can result in a higher gain-bandwidth product of low-noise amplifier (LNA) amplifier stages. The effect of the complex zero in the Z₁₁ 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 Z₁₁ wideband loads in two stages) achieves a 24.4-32.3-GHz bandwidth (27.9 % fractional bandwidth), a peak S₂₁ 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.

I. Introduction

Phased-array transceivers [1]–[3] are required to overcome path loss and realize advanced multiple-input–multiple-output (MIMO) communication in emerging 5G networks in the 28-/38-GHz bands [4]. Since antenna arrays with high element count are needed, it is important for the transceiver circuits to be compact, scalable and energy-efficient. In particular, wideband low-noise amplifiers (LNAs) that can cover contiguous and/or widely separated narrowband channels of a diverse spectrum [3] with low cost and small die area are of high interest, especially in the 60-GHz [5]–[7] and the 28-GHz bands [3], [8], [9]. Recently, coupled LC resonators have received wide interest in various millimeter-wave (mm-wave) circuits, including LNAs [3], [8]–[10], wide-tuning voltage-controlled oscillators (VCOs) [11], [12], and power amplifiers (PAs) [13], [14]. The resonators can be coupled capacitively, inductively (through an explicit inductor), or magnetically (through a mutual inductance), and each result in a fourth-order transfer function. Magnetic coupling is usually preferred since it results in a lower ripple for a given bandwidth [6]. Recent mm-wave LNAs in this class exclusively use the transimpedance () of weakly coupled transformer-coupled resonators as wideband loads [3], [5], [6].