A 2.4 GHz and 5.8 GHz tunable low-noise amplifier using PIN diode

In this paper, a tunable low-noise amplifier (LNA) is developed. The operation bands of the LNA can be switched between 2.4 GHz and 5.8 GHz by controlling a PIN diode in the output matching network. At the forward bias state of the PIN diode, the LNA operates at 2.4 GHz, the measured gain is 16 dB and the noise figure is below 0.6 dB within a bandwidth of 100 MHz. At the reverse bias state of the PIN diode, the LNA works at 5.8 GHz, the measured gain is 9.7 dB and the noise figure is below 1.7 dB within a bandwidth of 200 MHz. Compared with the wideband LNA covering 2.4GHz and 5.8GHz bands, efficient improvement in gain and noise figure is observed.