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This article presents a 22.6–39.2-GHz reflectionless receiver (RX) capable of reducing the in-band intermodulation and high-order mixing products. Such RX consists of an absorptive IF amplifier, a double-balance passive mixer, and a dual-path noise-canceling low noise amplifier (LNA). The absorptive IF amplifier is utilized to suppress the out-of-band signal reflected back to mixer, which can reduce the intermodulation and high-order mixing products caused by the remixing of the out-of-band signals. Meanwhile, the dual-path noise-canceling LNA is used for achieving low noise figure (NF) in a wide frequency range. To verify the aforementioned principle, a reflectionless RX is implemented and fabricated using a conventional 28-nm CMOS technology. The measurement shows the minimum NF of 3.6 dB and the peak input third-order intercept point (IIP3) of −11.7 dBm. Besides, the proposed RX can support multi-Gb/s, 256-quadratic amplitude modulation (QAM)/1024-QAM modulation signals. [ABSTRACT FROM AUTHOR]

A novel architecture of a digital modulated polar phased-array transmitter with phase modulation (PM) phase-shifting and feed-forward controlled dynamic matching (FFCDM) is presented in this article. Phase-shifting in a PM signal path is utilized in each element, which shares many components including a phase modulator, baseband, and IF components. The characteristics of the proposed architecture are analyzed. With a constant envelope of PM signals, the implicit nonlinearity of the phase shifter in this architecture has low impact on the linearity performance of a phased-array system. Meanwhile, low phase error can be achieved by high-resolution phase interpolation with the digital predistortion (DPD) technique. Efficiency for both saturated and 6-dB back-off power is enhanced by digital power amplifier (DPA) with FFCDM. As a proof of concept, a 3–7 GHz 4-element phased-array transmitter is designed and fabricated in 40-nm CMOS based on the proposed method. The measured root-mean-square (rms) phase error of 0.3°, effective phase shifting resolution of 9-bit, and peak system efficiency of 38.2% are achieved. For 40 MHz 64-QAM modulation signal, it exhibits EVM of 5.38% and 5.37%, $P_{\text {out}}$ of 14.30 and 14.46 dBm, and PAPR of 7.08 and 6.97 at 3.5 and 5.2 GHz, respectively. The measured peak EIRP is 35.6 dBm with a unit antenna gain of 2.98 dBi at 5 GHz. The radiation patterns with 0°, 15°, 30°, and 45° steering are measured based on monopole antennas. Meanwhile, the array achieves < 4.7% and < 5.9% EVM for 64-QAM signals with bandwidths of 20 and 40 MHz, respectively. [ABSTRACT FROM AUTHOR]