Wim Van Thillo

A low-power 57-to-66GHz transceiver in 40nm LP CMOS with −17dB EVM at 7Gb/s

Obtaining sufficient EVM in all four 1.76GHz bandwidth chann1.76GHzels specified by IEEE 802.15.3c and the emerging 802.11ad high-data-rate wireless communication standards for modulations as complex as QAM16 is a challenge. Recently reported implementations are therefore restricted to just 1 or 2 channels. Wireless applications often use digital low-power (LP) CMOS technology to implement single-chip transceivers. The high Vt and the thin metal interconnect layers constrain the mm-Wave circuit performance. This paper presents a digital LP 40nm CMOS 60GHz transceiver (TRX) IC that obtains an EVM better than -17dB in all 4 channels.

A fifth-order 880MHz/1.76GHz active lowpass filter for 60GHz communications in 40nm digital CMOS

For the analog baseband section of a 60GHz receiver for fast download applications, two 5th order Butterworth filters with cutoff frequency of 880MHz and 1.76GHz for 60GHz radios are implemented in 40nm low power digital CMOS, using Sallen and Key biquads. Drawing 25/21mA from a 1.1V supply, an IIP3 of −13/−12dBV to −16.7/−18.3dBV and an input-referred noise of 320/280µVrms are measured for the 880/1760MHz filter.

13.5 A 4-antenna-path beamforming transceiver for 60GHz multi-Gb/s communication in 28nm CMOS

Millimeter-Wave transceivers with beamforming capabilities, such as the one presented in this work, are a key technology to reach 4 or 6Gb/s at 10m range with the IEEE 802.11ad standard. Moreover, for mm-Wave access in 5G it will also be necessary to boost peak data-rates far beyond 1Gb/s at hundreds of meters in small cells. Transceiver architectures with beamforming often combine superheterodyne with RF beamforming [1], leading to a high power consumption and a suboptimal RX noise figure due to losses in the beamforming circuitry. In contrast, the 57-to-66GHz TRX IC presented in this paper, whose architecture is depicted in Fig. 13.5.1, uses direct conversion and analog baseband beamforming. Direct-conversion radios are inherently simpler than superheterodyne and do not have to cope with the image frequency, but on the other hand they may suffer from pulling of the PA on the VCO. In this work this is avoided by the non-integer ratio of 2.5 between the operating frequency and the 24GHz PLL that subharmonically injection locks a 60GHz quadrature oscillator (Fig. 13.5.2).

Digitally Modulated CMOS Polar Transmitters for Highly-Efficient mm-Wave Wireless Communication

A polar transmitter (TX) is implemented at 60 GHz, enabling a power amplifier (PA) to operate in saturation where efficiency is highest, even when handling higher order modulations such as QPSK and 16-QAM. The phase path is upconverted by I-Q mixers, while the amplitude path modulates an RF-DAC. Aimed at 802.11ad applications, the 10 GS/s (i.e., 6x-oversampled) polar TX realizes more than 30 dB alias attenuation, and the input bandwidth exceeds 3.1 GHz. The PA saturated output power is 10.8 dBm with 29.8% drain efficiency at the maximum RF-DAC code. Average output power is 8.1 dBm with 22.3% drain efficiency at -20.7 dB EVM for QPSK modulation without RF-DAC predistortion. The corresponding 16-QAM values are: 7.2 dBm average output power with 19.8% efficiency at -16.5 dB EVM. With predistortion, a QPSK modulated output achieves 5.3 dBm average power with 15.3% efficiency at -23.6 dB EVM, while 3.6 dBm average power with 11.6% efficiency at -18.1 dB EVM is realized for 16-QAM. For a sampling rate of 10 GS/s, the TX data rates are 3.33 Gb/and 6.67 Gb/s for QPSK and 16-QAM, respectively. Implemented in 40 nm bulk-CMOS, the core circuit occupies 0.18 mm2 core of the 2.38 mm2 total die area, and consumes 40.2 mW from a 0.9 V supply.

Air Interface and Physical Layer techniques for 60 GHz WPANs

Thanks to the unprecedented availability of huge bandwidth, the capacity offered by wireless systems in the 60 GHz band can exceed the mythical barrier of 1 Gbps wireless, enabling the deployment of new applications. However, the performance can be limited by the non-ideality of the analog front-ends, multipath fading and the difficulty to achieve a reasonable link budget at high data rates. The goal of this paper is to introduce high rate communications in the 60 GHz band and the associated challenges. We will first introduce WPANs in the 60 GHz band, describing the possible applications, the propagation channel and the standardization context. Furthermore, based on the characteristics of the propagation channel, we will show that beamforming is desirable to boost the link budget, reduce interference and, in some cases, reduce multipath. Next, we will introduce candidate PHY layer solutions that at the same time meet the throughput requirements and relax the analog front-end design. Our solutions rely on the combination of block transmission combined with (nearly) constant envelope modulation: this provides low peak-to-average power ratios, easy equalization, good spectral properties and modest front-end requirements in terms of phase noise and ADC resolution. The receiver signal processing associated with the modulation techniques will be described and link level simulation results will be provided, highlighting the front-end friendliness of the modulation technique