This paper presents the first reported 28-GHz phased-array IC for 5G communications. Implemented in 130-nm SiGe BiCMOS, the IC includes 32 TRX elements and features concurrent independent beams in two polarizations in either TX or RX operation. Circuit techniques to enable precise beam steering, orthogonal phase and amplitude control at each front end, and independent tapering and beam steering at the array level are presented. A TX/RX switch design is introduced which minimizes TX path loss resulting in 13.5 dBm/16 dBm Op1dB/Psat per front end with >20% peak power added efficiency of the power amplifier (including switch and off-mode LNA) while maintaining a 6 dB noise figure in the low noise amplifier (including switch and off-mode PA). Comprehensive on-wafer measurement results for the IC across multiple samples and temperature variation are presented. A package with four ICs and 64 dual-polarized antennas provides eight 16-element or two 64-element concurrent beams with 1.4°/step beam steering (<0.6° rms error) across a ±50° steering range without requiring calibration. A maximum saturated effective isotropic radiated power of 54 dBm is measured in the broadside direction for each polarization. Tapering control without requiring calibration achieves up to 20-dB sidelobe rejection without affecting the main lobe direction.

A 28-GHz 32-Element TRX Phased-Array IC With Concurrent Dual-Polarized Operation and Orthogonal Phase and Gain Control for 5G Communications

This work presents a highly integrated 57–64 GHz 4-channel receiver 2-channel transmitter chip targeting short range sensing and large bandwidth communications. The chip is housed in an embedded wafer level ball grid array package. The package includes 6 integrated patch antennas realized with a metal redistribution layer. The receiver patch antennas have a combined antenna gain of $\approx 10$ dBi while each transmitter antenna has a gain of $\approx ~6$ dBi. The chip features a wide tuning range integrated VCO with a measured phase noise lower than −80 dBc/Hz at 100 kHz offset. Each of the differential transmitter channels shows a measured output power of 2–5 dBm over the complete frequency range. In addition, one transmitter channel features a modulator that can be digitally programmed to operate in either radar or communication mode. Each of the receiver channels has a measured conversion gain of 19 dB, a single-sideband noise figure of less than 10 dB and an input referred 1 dB compression point of less than 10 dBm. With all channels turned on the chip consumes a current of 300 mA from a 3.3 V supply. The functionality of the chip is demonstrated for both sensing and short range wireless communications.

A Highly Integrated 60 GHz 6-Channel Transceiver With Antenna in Package for Smart Sensing and Short-Range Communications

The forthcoming 5G cellular network is expected to overlay millimeter-wave (mmW) transmissions with the incumbent micro-wave ( $\mu\text{W}$ ) architecture. The overall mm- $\mu\text{W}$ resource management should, therefore, harmonize with each other. This paper aims at maximizing the overall downlink (DL) rate with a minimum uplink (UL) rate constraint, and concludes: mmW tends to focus more on DL transmissions while $\mu\text{W}$ has high priority for complementing UL, under time-division duplex (TDD) mmW operations. Such UL dedication of $\mu\text{W}$ results from the limited use of mmW UL bandwidth due to excessive power consumption and/or high peak-to-average power ratio (PAPR) at mobile users. To further relieve this UL bottleneck, we propose mmW UL decoupling that allows each legacy $\mu\text{W}$ base station (BS) to receive mmW signals. Its impact on mm- $\mu\text{W}$ resource management is provided in a tractable way by virtue of a novel closed-form mm- $\mu\text{W}$ spectral efficiency (SE) derivation. In an ultra-dense cellular network (UDN), our derivation verifies mmW (or $\mu\text{W}$ ) SE is a logarithmic function of BS-to-user density ratio. This strikingly simple yet practically valid analysis is enabled by exploiting stochastic geometry in conjunction with real three-dimensional (3-D) building blockage statistics in Seoul, South Korea.

Tractable Resource Management With Uplink Decoupled Millimeter-Wave Overlay in Ultra-Dense Cellular Networks

Emerging millimeter-wave (mmWave) and Terahertz (THz) systems is a promising revolution for next-generation wireless communications. In this paper, we study an indoor multi-user mmWave and sub-THz system with large antenna arrays, where two different types of architecture, the fully-connected structure and the array-of-subarray structure, are investigated. Specifically, the Doherty power amplifier (PA) is adopted to improve the PA efficiency of the system, and the associated nonlinear system power consumption models with insertion power loss are developed. By capturing the characteristics of the mmWave and sub-THz channels, we design different hybrid beamforming schemes for the two structures with low complexity. We further compare the achievable rates of the two structures and show that, with the insertion loss, the achievable rate of the array-of-subarray structure is generally larger than that of the fully-connected structure. Moreover, we propose the optimal power control strategies for both structures to maximize the energy efficiency of the system and demonstrate that the energy efficiency of the array-of-subarray structure outperforms that of the fully-connected structure. Simulation results are provided to compare and validate the performance of the two structures, where the array-of-subarray structure shows a great advantage over the fully-connected structure in both spectral efficiency and energy efficiency.

Energy-Efficient Design of Indoor mmWave and Sub-THz Systems With Antenna Arrays

This article presents the first 39-GHz phased-array transceiver (TRX) chipset for fifth-generation new radio (5G NR). The proposed transceiver chipset consists of 4 sub-array TRX elements with local-oscillator (LO) phase-shifting architecture and built-in calibration on phase and amplitude. The calibration scheme is proposed to alleviate phase and amplitude mismatch between each sub-array TRX element, especially for a large-array transceiver system in the base station (BS). Based on LO phase-shifting architecture, the transceiver has a 0.04-dB maximum gain variation over the 360° full tuning range, allowing constant-gain characteristic during phase calibration. A phase-to-digital converter (PDC) and a high-resolution phase-detection mechanism are proposed for highly accurate phase calibration. The built-in calibration has a measured accuracy of 0.08° rms phase error and 0.01-dB rms amplitude error. Moreover, a pseudo-single-balanced mixer is proposed for LO-feedthrough (LOFT) cancellation and sub-array TRX LO-to-LO isolation. The transceiver is fabricated in standard 65-nm CMOS technology with flip-chip packaging. The 8TX–8RX phased-array transceiver module 1-m OTA measurement supports 5G NR 400-MHz 256-QAM OFDMA modulation with −30.0-dB EVM. The 64-element transceiver has a EIRPMAX of 53 dBm. The four-element chip consumes a power of 1.5 W in the TX mode and 0.5 W in the RX mode.

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A 39-GHz 64-Element Phased-Array Transceiver With Built-In Phase and Amplitude Calibrations for Large-Array 5G NR in 65-nm CMOS

This paper presents a 60-GHz direct-conversion RF front-end and baseband transceiver including analog and digital circuitry for PHY functions. The 65-nm CMOS front-end consumes 319 and 223 mW in transmitting and receiving mode, respectively. It is capable of more than 7-Gb/s 16QAM wireless communication for every channel of the 60-GHz standards, which can be extended up to 10 Gb/s. The 40-nm CMOS baseband including analog, digital, and I/O consumes 196 and 427 mW for 16QAM in transmitting and receiving modes, respectively. In the analog baseband, a 5-b 2304-MS/s ADC consumes 12 mW, and a 6-b 3456-MS/s DAC consumes 11 mW. In the digital baseband integrating all PHY functions, a (1440, 1344) LDPC decoder consumes 74 mW with the low energy efficiency of 11.8 pJ/b. The entire system including both RF and BB using a 6-dBi antenna built in the organic package can transmit 3.1 Gb/s over 1.8 m in QPSK and 6.3 Gb/s over 0.05 m in 16QAM.

N. Shimasaki

Papers

Full Four-Channel 6.3-Gb/s 60-GHz CMOS Transceiver With Low-Power Analog and Digital Baseband Circuitry