An Adaptive Beamforming Technique for UWB Impulse Transceiver

A two-channel beamforming ultra-wideband (UWB) impulse transceiver chip, which includes a beam steering TX controlled by a fractional delay locked loop and an adaptive RX that can self-tune the beamforming to the direction of incident pulses, is presented. The dual-channel timed array transmitter can generate UWB pulses in two separate transmitter paths with tunable path delay difference of 0~250 ps to achieve beam-steering capability. Each beamforming receiver channel has a measured continuous time delay between 0~250 ps. The proposed beamformer could provide maximum scan angle of up to ±60° for two antennas with about 8-cm spacing. Fabricated in 0.18- $\mu \text{m}$ CMOS, the TX can beam steer across the full spatial range with resolution of 4°, and the RX can continuously scan the full range with resolution of 3°. The transmitter consumes 37 mA at 10 Mbps and receiver consumes 84 mA under 1.8-V power supply.