A High Linearity Wideband Lna With An Excellent Gain Flatness For S-Band Application

In this paper, a wideband low noise amplifier (LNA) of bandwidth 2-4 GHz, gain more than 31 dB, flatness fluctuating in 0.44 dB and maximum noise figure less than 2.2 dB is proposed. The LNA is in a two-stage cascade structure and the same bias voltage conditions is used by each stage. The impedance matching is adjusted by the capacitive feedback at low frequency and the resistance feedback at high frequency. Thus the wide-band matching and flat gain is realized. The output power at 1 dB compression point is more than 14.8 dBm and a compact chip area is 2mmx1.58mm including RF pad. The LNA features broad bandwidth, relatively high gain, low noise figure and an excellent gain flatness, and will be further used in S-band application.