Concurrent design of Schottky diode limiter and LNA

Abstract

In this paper concurrent design of Schottky diode based limiter and low noise amplifier (LNA), based on noise matching, is investigated to achieve minimum noise figure (NF) of the receiver chain. In design procedure of the LNA, the noise figure is minimum, gain at central frequency is 14.5 dB, and limiter structure tolerates up to 5 W continuous wave input power. In the proposed concurrent design, a pass-band filter is applied at the LNA output to attenuate undesired out-of-band signals. In the proposed design, the limiter-LNA is implemented with a 0.25 µm gate length AlGaAs/InGaAs pHEMT process. Measured noise figure of chain is 2.7 dB and average gain over 8.5–9.5 GHz frequency range and the gain at 9 GHz center frequency are 10 dB and 14.5 dB respectively. The performance results of proposed matching network are compared with traditional 50 Ω matching networks in limiter-LNA with identical circuit specifications.