Niels Van Thienen

10.2 An FSK plastic waveguide communication link in 40nm CMOS

Technology scaling has enabled RF-CMOS circuits that operate in the millimeter-wave frequency range (30 to 300GHz) where large bandwidths are available. These bandwidths can be exploited to increase data-rates of wireless communication links. Unfortunately, free-space path loss (FSPL) limits the operating distance of wireless systems at these frequencies. A 5-meter link at 120GHz has an FSPL as high as 88dB. Therefore such wireless links are feasible only with highly directive antennas. This work uses a directive channel instead. At mm-Wave frequencies, the directive channel can be a low-cost plastic fiber or hollow tube, made from PP, PS or Teflon. These directive channels will guide electromagnetic waves with low loss from TX to RX [1-4]. As such, RF communication through a plastic fiber becomes an interesting alternative and complements existing solutions like wireline copper or optical fibers. This paper presents an entire communication link that uses a continuous-phase frequency-shift keying (CPFSK) TX and RX. We report on 120GHz 40nm CMOS TX and RX chips, the connector solution, and the plastic channel. Data-rates up to 12.7Gb/s over 1m, transmission lengths up to 7m at 2.5Gb/s and an energy efficiency of 1.8pJ/b/m for 4m and 7.4Gb/s are achieved for the complete communication link. All these results are for a BER 10-12. Compared to previous work, measurements also show the link still works for a bending radius of only 25mm, thanks to the selection of a high carrier frequency.

A 160-GHz three-stage fully-differential amplifier in 40-nm CMOS

This paper presents a 160-GHz fully-differential power amplifier in 40-nm CMOS. A tapered gate-connection network was optimized which results in a reduction of the gate resistance and allows to achieve a maximum gain of 11.6 dB with a 3-dB bandwidth of 24 GHz from the three-stage amplifier. The measured saturated output power is 4.1 dBm and the measured 1-dB compression power is 1.5 dBm. The matching networks are implemented using on-chip transformers and slow-wave transmission lines. Differential and common-mode stability is obtained by adding cross-coupled capacitance to the differential pairs and series resistance to the bias network respectively. The amplifier core occupies an area of 0.063 mm2 due to the compact design and the use of slow-wave transmission lines. With a supply voltage of 1.0 V, the amplifier consumes a DC current of 42 mA.

Polymer Microwave Fibers: A blend of RF, copper and optical communication

This paper discusses some of the recent advances and challenges that lie ahead for Polymer Microwave Fibers (PMF). PMF is a communication concept that combines mm-wave chips, metal couplers and cheap plastic fibers. It has some unique benefits over copper wireline and optical which can give it a preferred solution for low-cost, low-weight robust high-speed data-communication such as automotive and industrial Ethernet, consumer-oriented connectivity, signal distribution and more.

A Multi-Gigabit CPFSK Polymer Microwave Fiber Communication Link in 40 nm CMOS

This paper presents a multi-gigabit communication link over a polymer microwave fiber (PMF). A polymer fiber is a light-weight and low-loss channel at millimeter-wave (mm-Wave) frequencies. PMF is a promising, robust and low-cost technology to complement copper or optical links for high-speed applications with transmission distances up to several meters. The high carrier frequency of 120 GHz ensures low bending losses for small bending radii and features a large absolute bandwidth, which can be exploited to achieve high data rates with a simple modulation scheme. The used continuous-phase frequency shift keying (CPFSK) modulation results in a power-efficient system at both the TX and the RX side. We report on 120 GHz 40 nm bulk CMOS TX and RX chips, the fiber and the coupling solution between the chips and the fiber. Data rates up to 12.7 Gbps over 1 meter, transmission lengths up to 7 meters at 2.5 Gbps and a link energy efficiency of 1.8 pJ/b/m for 4 meters and 7.4 Gbps are achieved for the complete communication link.

An 18Gbps polymer microwave fiber (PMF) communication link in 40nm CMOS

A high-speed polymer microwave fiber (PMF) communication link is implemented in a 40nm bulk CMOS technology, by making use of two-tone CP-FSK modulation and a carrier frequency of 120GHz. The presented transceiver and enhanced coupler, with a loss of only 3.4dB, allows communication over a distance of 15m at 1.5Gbps. Data rates up to 17.7Gbps were achieved over a link distance of 1m with a BER <; 10-12. The maximum product of data rate and distance is 60.8Gbps.m over a distance of 8m, resulting in an energy efficiency of only 1.2pJ/bit/m. The transmitter has an output power level of -1.9dBm at 120GHz and a DC power consumption of 11.1mW, the receiver consumes 59.6mW. The transmitter and receiver occupy an active area of respectively 0.025mm2 and 0.43mm2 in 40nm CMOS.