A Dual-Band GNSS RF Front End With a Pseudo-Differential LNA

This brief presents the design and the implementation of a dual-band radio-frequency (RF) front end for global navigation satellite system (GNSS) receivers. The dual-band RF front end is composed of a pseudo-differential low-noise amplifier (LNA), down-conversion mixers, and programmable gain amplifiers (PGAs), and can be configured to operate at 1.2 and 1.57 GHz, respectively. The pseudo-differential LNA incorporates an active single-ended-to-differential conversion using capacitive coupling compensation for an improved phase and amplitude imbalance. The high-linearity PGA has a tunable gain range of 18 dB with a 6-dB gain step and a 0.2-dB gain ripple across a 30-MHz band width. The proposed RF front end achieves a maximum voltage gain of 68/65 dB, a noise figure of 2.4/2.6 dB, and an input-referred 1-dB compression point of -42/-39 dBm at the 1.2-/1.57-GHz bands. The receiver draws 10 mA from a 1.8-V power supply. The RF front end is implemented in a 0.18-μm CMOS process, occupying a die area of 1.0 × 0.5 mm².