A 38.5-to-60.5 GHz LNA with Wideband Combiner Supporting Cartesian Beamforming Architecture

Current millimetre-wave (mmW) 5G NR standard supports multiple bands at 24.5/28/37/39/43/47GHz for communications. To cover several bands of the 5G NR and reaching lower end of unlicensed 60GHz band for 802.11ad, this work presents a wideband phased array front-end with LNA and two VGAs for scalar-only weighting function, and a wideband combining network of each signal weight in mmW domain for beamforming. In this work, two array elements are combined in two cascaded stages for extremely wideband operation. Combined load resonances are distributed and adjusted appropriately in each of the combining stages to achieve a flat response over the band of 38.5–60.5GHz. A single array path achieves rms gain of 8.5–12.5dB, noise figure of 6.2–8.1dB, and IP1dB of -33 to–26dBm. The measurements show ≈ 6dB of array gain when the two phased array elements are combined in phase with +0.6dB to -0.4dB maximum gain error in the mmW VGAs. The prototype is implemented using 28nm CMOS.