In this paper, AlGaN/GaN/AlGaN/GaN high electron mobility transistor (HEMT) with 0.25 um gatelength have been designed on an SIC-4H substrate. DC and Noise characteristics of AlGaN/GaN/AlGaN/GaN HEMT with 0.25 um gate-length at microwave frequencies have been explored. The simulation has been performed by using the Silvaco software. The extrinsic transconductance of the device was 350 ms/mm. Also, device exhibited current drive capability as high as 1750 ma/mm. The device has demonstrated high unity current gain cutoff frequency (ft) of 200 GHz. The microwave noise characteristics of the device were determined from 0 to 20 GHz at different drain biases and drain currents. At a gate bias of-3 V and drain bias of 10 V, device exhibited a minimum noise figure (NFmin) of 0.35 dB and maximum associated gain (Gma) of 24.35 dB at 10 GHz. The noise resistance of device is 7.2 ohm at 10 GHz, which is very suitable for low noise applications in X-band frequency range. These results indicates the capability of AlGaN/GaN HEMT for low noise and high power amplifiers.

In this paper, design and simulation of a 10 GHz Low Noise Amplifier (LNA) for Wireless communication systems have been explored. The simulation result has been performed by using the Agilent Advanced Design System (ADS) software. Tuning and optimization tools of ADS software have been used to optimize results. The High Electron Mobility Transistor (HEMT) based on GaN is used for decreasing of Minimum Noise Figure (NFmin) of LNA. Also, for more decreasing NFmin of LNA radial stub elements are implemented in biasing network. We have designed a 10 GHz LNA based on three design manner basing on the lumped, the distributed and radial stub elements. The designed amplifier offers forward gain of 15.72 dB with the noise figure of 1.09 dB at 10 GHz. The input return loss (S11) is equal to-9.635 dB at 10GHz. The output return loss (S22) is equal to-10.009 dB at 10GHz. Also, the isolation (S12) of proposed structure is equal to-22 dB at 10 GHz. The simulation result have shown that the forward gain and noise figure of 10 GHz LNA are optimized noticeably with respect to the pervious works.