A CMOS RF front-end transceiver for MB-OFDM UWB radio

Abstract

Ultra-wideband technology is emerging as a solution for the IEEE 802.15.3a (TG3a) standard. The purpose of this standard is to provide a specification for a low-cost, low complexity, low power, and high data-rate (up to a few Gbps) wireless connectivity among devices within personal operating space (up to 10-m). The data-rate must be high enough (at least 110 Mbps) to satisfy Wireless Personal-Area Networks (WPAN) communications. UWB system is very unique system compared to previous narrowband systems in terms of its wide bandwidth and severe interferers’ environments. First, the bandwidth (3.1 to 10.6-GHz) of 7.5-GHz in the UWB system is the widest one among existing wireless system. All circuits for UWB systems are required to enough wideband bandwidth or high sampling speed. The 802.11a/b/g signals are critical interferers for the UWB system, because they just are far away a few hundreds MHz, which can’t be efficiently attenuated by pre-BPF. Accordingly, wide bandwidth and strong interferers, in the UWB system, give many design challenges to RF circuit designers for their hardware implementation. This paper describes intensively RF design issues in the UWB system; wideband input matching, wide bandwidth, a fast-hopping frequency synthesizer, and so on. This paper also contains design examples such as wideband low noise amplifier, broadband amplifier, up- and down-conversion mixer, single-to-differential conversion scheme, and a fast hopping frequency synthesizer. Finally, an RF front-end receiver optimized for 3 ~ 5 GHz MB-OFDM UWB radio (Mode 1) are described for design and implementation. For the digital/analog system-on-chip (SoC), the proposed RF front-end receiver is implemented using 0.18 $\mum$ CMOS technology. It adopts double conversion architecture and also incorporates frequency planning that simplifies the design of the fast-hopping frequency synthesizer. The proposed frequency synthesizer has the fewest nonlinear components with one PLL fo...