A 1.7-2.7 GHz High Linear Low Noise Amplifier

In order to meet the high linearity and low noise requirements in the receiving channels of 5.5G, this paper proposes a low noise amplifier (LNA) with a shutdown function (PD) based on the 0.25 μm GaAs pHEMT. Utilizing a cascade structure, the amplifier incorporates a RC feedback network, along with active bias network for the common-source and common-gate to enhance linearity. Through input and output matching, minimum noise and maximum power output are achieved. Experimental results demonstrate that the chip operates at the frequency range of 1.7-2.7 GHz with a gain of 18–22 dB. The input and output return loss are less than -10 dB, with a 1dB output compression point $(\mathrm{P}_{1\text{dB}})$ of 22.5 dBm. The noise figure is less than 1 dB with an input third-order intercept point (IIP3) of 23 dBm. The switching time of the shut-down and the turn-on is less than 20 ns and 50 ns, respectively.