Kristof Vaesen

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.

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.

Integrated Wilkinson Power Dividers in C-, Ku- and Ka-Band in Multi-Layer Thin-Film MCM-D

We report on the design and measurement of Wilkinson splitters in C-, Ku-and Ka-band in multi-layer thin film MCM-D. The designs have been performed using a full CPW design library offering automated layout. An excellent agreement between the measured and simulated S-parameters has been obtained indicating the high accuracy of the implemented transmissionline-, resistor-and discontinuitymodels. For the 7 GHz Wilkinsons, 6 design approaches have been compared and realized: a fully distributed design, a meandered design using a capacitively loaded transmission line, a design with high impedance lines and capacitive compensation at the ends and 3 lumped element designs with an increasing degree of compaction. The fully distributed design has the best performance (isolation better than ¿25 dB, return loss better than ¿20 dB with an insertion loss of ¿3.33 dB over the 6.5-7.6 GHz band) and is the most wideband but consumes the largest area. Distributed 14 GHz and 30 GHz designs have also been made with very good accuracy and performance.

A 54–69.3 GHz dual-band VCO with differential hybrid coupler for quadrature generation

This paper presents a 40nm CMOS transformer-based dual-band VCO with differential hybrid coupler for I/Q generation. The average phase noise of the combination over the 54 to 69.3GHz tuning range is -90dBc/Hz at 1MHz offset while the best FOM value is 177dB. Along the wide tuning range from 54 to 67GHz, the I/Q mismatch of the hybrid coupler is less than 3°. The area of the hybrid is only 60μm-65μm.

Design and Tuning of Coupled-LC mm-Wave Subharmonically Injection-Locked Oscillators

This paper analyzes and demonstrates the use of coupled-LC tanks to enlarge the locking range (LR) of millimeter-wave (mm-wave) subharmonically injection-locked oscillators. Design guidelines are derived from a simplified analysis. Different techniques are proposed to tune the coupled-LC tank. A mm-wave subharmonically injection-locked quadrature voltage-controlled oscillator in 40-nm CMOS verifies the proposed approach. The LR is larger than 2 GHz over a 55-63-GHz tuning range. An on-chip envelope detector facilitates the tuning of the coupled-LC tank. The phase noise and the quadrature-phase imbalance are uniform over almost the whole LR.

An 80-GHz low noise amplifier resilient to the TX-spillover in phase-modulated continuous-wave radars

We propose an 80GHz low noise amplifier capable of linearly handling and canceling a TX spillover up to −20dBm. The cancellation circuit is mainly intended for phase-modulated continuous-wave radar. The circuit is implemented in a 28nm CMOS technology and achieves a gain, NF and iP1dB of 15.2dB, 5.5dB and −15.5dBm respectively, while attenuating the TX spillover by 13.5dB.

A load-pull wafer-mapper

This paper describes an automated load-pull measurement testbench for the characterization of GaN power HEMTs. The setup was built around a vector network analyzer (VNA) and an electromechanical tuner. The setup is combined with a semi-automatic wafer-stepper, allowing for complete large-signal wafer-mapping. Both calibration and measurement procedure are explained in mathematical detail.

Area Optimized Thin Film Coupled Inductor Band Pass Filters with Integrated Baluns

Modern commercial telecommunication devices tend to integrate more and more functionality on a single chip, the so called SoC (System on a Chip) approach. This results in ultra-compact and low cost realization. However antenna filters and diplexer are still important parts in the transmit/receive chain for which until now no on-chip solution is possible that meets the requirements. In this work we show how it is possible to realize high quality, ultra compact and low cost filters using IMECs general purpose RF thin film technology. Narrow band pass filters can be realized in different fashions, but they all consist of coupled resonators. High Q-values of the resonators are required to realize narrow band, low insertion loss filters. A drop in Q-value will result in a fast increase of insertion loss [1]. The most conventional way is to create these resonators by LC-tanks and couple them to each other using an inductor or a capacitor. The main goal in our design exercise was to reduce the area requirements as much as possible. We did this by omitting this coupling component and used the mutual inductance of the closely spaced tank inductors as coupling factor. In this manner we took advantage of the otherwise unwanted effect of inductor coupling and gained in area both by omitting the coupling component and by closely spacing the inductors.