Design of 10 to 12 GHz Low Noise Amplifier for Ultrawideband (UWB) Syste

Balanced amplifier is the structure proposed in this article, it provides better performance. In fact, the single amplifier meets the specification for noise figure and gain but fails to meet the return loss specification due to the large mis-matches on the input & outputs. To overcome this problem one solution is to use balanced amplifier topography. In this paper, a wide-band and highgain microwave balanced amplifier constituted with branch line coupler circuit is proposed. The amplifier is unconditionally stable in the band [9-13] GHz where the gain is about 20dB. The input reflection (S11) and output return loss (S22) at 11 GHz are -33.4dB and -33.5dB respectively

Performance Analysis of Low noise amplifier using Combline Bandpass Filter for X Band Applications

This paper describes a procedure for designing broadband low noise amplifier for X-Band applications. The design and implementation is based on HEMT transistors AFP02N2-00 of Alpha Industries®. The matching circuit used for modeling the microwave amplifier is the quarter-wave transformers impedance matching technique associated to combline bandpass filter.  The proposed amplifier is implemented on a substrate of epoxy FR4 with a central frequency of 11GHz and a fractional bandwidth of 0.18% and is designed to be used in radar reception systems. The results show that the proposed LNA is unconditionally stable with a simulated gain of 20dB over the working frequency range of [9.5−12.5] GHz