UC Davis

With an increasing demand for accurate indoor and outdoor ranging and location, ultra-wideband (UWB) technology has drawn much attention in the field of smartphones, intelligent vehicles, health monitoring, and internet-of-things (IoT) ever since Federal Communication Commission (FCC) released unlicensed spectrum of 3.1 GHz to 10.6 GHz for UWB applications in year 2002, due to its capability in providing centimeter-level location accuracy under impulse-radio (IR) operation. The high precision is thanks to the ultra-short pulse characteristic that has much better immunity to noise and multi-path interference compare to conventional narrow-band signals.This paper presents an IEEE 802.15.4a/4z compliant integrated IR-UWB coherent transceiver that supports all channels in Band 2 from 6.5 GHz to 10 GHz. A wideband phase-locked loop (PLL) with dual LC quadrature voltage controlled oscillators (QVCOs) is proposed that covers more than 5-GHz frequency range. The PLL features a phase noise of −99.8 dBc/Hz at 1-MHz frequency offset and a RMS jitter of 2.3 ps, which ensures reliable coherent operation. The quadrature clocks are also used in the proposed I/Q receivers (RX) to improve the signal-to-noise (SNR) ratio. On the transmitter (TX) side, to ensure maximum output signal power under different channels and data rates without violating FCC regulation, a digital pulse shaper that controls pulse envelope, pulse width, and pulse amplitude is implemented using a symmetric highly programmable ring counter and 18 parallel digital power amplifier (DPA) stages. Implemented in a 28-nm CMOS process with a nominal supply voltage of 0.9 V, the overall chip occupies an area of 1.46mm2. The TX supports channel 5∼15 with a peak pulse repetition frequency (PRF) of 499.2 MHz. Including a 2-dB loss in the measurement setup, the transmitter has a maximum output swing of 430mV and the power consump-tion is 1.3 nJ/pulse at a PRF of 15.6 MHz. The RX consumes a total power of 28.6mW and is able to demodulate and recover transmitted burst position modulation (BPM) and binary phase-shift key (BPSK) data bits.