A Multi-Gbps, Energy Efficient, Contactless Data-Communication Link for Machine-to-Machine (M2M) Interaction with Rotational Freedom
This paper presents a low cost, compact, short-reach contactless data link designed for M2M applications requiring a full 360deg rotational freedom. Full rotational freedom is enabled by a 16GHz split-ring resonator based near field coupler which provides a fourth order bandpass characteristic with a 4GHz bandwidth and ~2dB insertion loss. The link employs 65nm CMOS TX and RX chipsets for OOK modulation and demodulation of a 16GHz carrier. The end-to-end contactless link is demonstrated with a variable gap (0.1mm to 0.7mm) and rotation angle (covering full range of 360deg with 45deg steps) between the TX and RX boards. Additionally, a BER<1E-12 is demonstrated up to 2.6Gbps over 0.5mm gap and with a full 360deg rotation capability and a competitive energy efficiency of ~20pJ/bit. This work demonstrates for the first time viability of robust, low-cost, energy efficient >2Gbps (BER<1E-12) rotational links operating at cm-wave frequencies without equalization.