Research And Design Of Low Noise Amplifier In RFIC For Satellite Navigation

Radio frequency receiver is one of the most important parts of Global Navigation Satellite System. Located at the first stage of the radio-frequency integrated circuit (RFIC), low noise amplifier (LNA) plays an important role in the radio frequency receiver whose performances are directly affected by the noise figure of LNA.Since the GPS (Global Positioning System) and"Beidou"are widely used in our country at present, a LNA which working at L1 band of GPS and B1/B2/B3 band of"Beidou"is presented in this paper. Firstly, performance indexes of LNA are introduced and the LNA proposed is implemented as an inductively degenerated common source amplifier after some research on topologies which are often used in the design of LNA. A well designed bandgap reference circuit is used in the current mirror to make sure that the LNA has an excellent performance. The LNA can work in four modes with different bias current for a control circuit is designed additionally. The inductor L_g located in the input port of the LNA is realized off chip because it can consume more die area for its large value. Meanwhile, the inductor L_d located in the output port of the LNA can be realized both on chip and off chip because of its small value. So the LNA1 with on-chip Ld and LNA2 with off-chip Ld are designed separately.The proposed LNA was designed based on TSMC 0.18μm RF CMOS process. The schematic, layout and post-layout simulation were done by Cadence and the simulation results are shown in the paper. The LNA was sent to fabricate and packaged. External inductors and capacitors are used to make the LNA well matched both in the input and output ports so that it can work effectively both on L1/B1 band and B2/B3 band. The test results of the well-matched LNA show that the LNA1's performance is not as good as the simulation results while the LNA2 works almost as well as the simulation results. After detailed analysis of the test results having been carried out, we initially find out some reasons why the LNA's performance goes down, which are helpful to our deep research.