A current-mode RF transmitter for 6-9 GHz MB-OFDM UWB application

This paper presents a current-mode 6-9 GHz RF transmitter for MB-OFDM UWB systems. The proposed current-mode transmitter consists of current-mode IQ LPF, current mirror amplifier, IQ up-conversion mixer （up-mixer）, differential power driver amplifier （PA） and high-speed divider with LO buffers for generating IQ LO signals. All circuits are designed to possess high linearity and wide bandwidth. The transmitter is fabricated in TSMC 0.13 p-m 1P8M RF CMOS technology with a die area of 1.56 mm2. Measurement results show that a maximum output power of -0.7 dBm with an LO leakage/sideband rejection ratio （LOL/SB RR） around -33/- 35 dBc is achieved, and that this transmitter excels the traditional voltage-mode counterpart in terms of high linearity （about ＋1 dBm output 1-dB compression point, ＋10 dBm output IP3 in average） with comparable power consumption （drawing 48 mA current from 1.2 V supply）.