Research On Dual-Mode Analog Baseband And Integration Of Receiver For OFDM UWB

By increasing the signal bandwidth significantly, ultra-wideband (UWB) achieves a high channel capacity and becomes an attractive solution to the ever-increasing data rate demands in wireless personal area networks (WPAN). It can achieve data transmission rate of up to480Mbps. In recently years, MB-OFDM has been the main standard for UWB technology. In2009, on consideration of the frequency usage and plan, the Industry and Information Product Department has proposed the Chinese UWB standard, which utilizes the Double Carrier-Orthogonal Frequency Division Multiplexing modulation. This paper focuss on the problem of receiver that can support both MB-OFDM and DC-OFDM standards. Solutions have been proposed and finally the receiver has been realized and tested.Firstly, the direct conversion architecture has been designed to support both standards. Link budget has been calculated and specifications for each building block of the receiver are proposed, which will guide the design of each block.The main differcenc of MB-OFDM and DC-OFDM lies in the different bandwith of the sub-bands. In order to support both standards, the cut off frequency of the channel select filter should be switchable. To solve this problem, a fifth order Chebyshev type Gm-C low pass filter is proposed. Both Gm and C can be tuned in the filter. A digital tuning system is used to calibrate the cut off frequency of the filter. This paper also proposes variable gain amplifier that inlcudes a local feedback and super source follower as the input stage. This amplifier can achieve good linearity in several hundred mega herz.The receiver is designed and fabricated in TSMC0.13μm CMOS process. Measurement results show that the receiver can support both standards. This is the first receiver that can support DC-OFDM UWB system.