Programmable-Gain Constant-IF-Bandwidth SiGe BiCMOS Upconversion Micromixer at 2.4/5.8 GHz Using Current-Mode Approach

Abstract

A 2.4/5.8-GHz dual-band programmable-gain upconverter with a constant IF bandwidth is demonstrated using 0.35-mu m SiGe BiCMOS technology. Using a current-mode design approach, the input IF bandwidth remains the same at different gain settings. A dual-band LC current combiner is used at the mixer RF output to combine differential signals to a single-ended one at two bands. Then, a wideband amplifier is cascaded after the dual-band mixer. The demonstrated upconverter achieves maximum gain of -4/-3 dB at 2.4/5.8 GHz, respectively. In addition, four gain steps with 5-dB gain difference between each step are controlled by a two-bit digital circuit. The total current consumption is 26 mA at a 4-V supply.