Concurrent multiband low noise amplifier with multisection impedance transformer

Abstract

In this paper, multiband low noise amplifier (LNA) with multi-section impedance transformer (MIT) as impedance matching is designed, fabricated and evaluated. MIT is used as input and output impedance matching because MIT has higher stability, large Q factor, and low noise than lumped component. MIT is easy to fabricate and measure. The aim of the research is to design multiband LNA with MIT at center frequencies located at 0.95 GHz for GSM, 1.85 GHz for WCDMA and 2.65 GHz for LTE. Designed and evaluated of the proposed multiband LNA with MIT is done by using advanced desain system (ADS). It shown from the simulated results that performances of the proposed LNA at center frequency of 0.950 GHz has return loss, S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> = -23.541 dB, insertion loss, S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> = 18.911 dB, noise figure, NF = 1.475 dB, VSWR = 1.143, and FoM = 8.38, respectively. At center frequency of 1.85 GHz, the proposed LNA has S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> = -23.771 dB, S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> = 12.858 dB, NF = 1.988 dB, VSWR = 1.139, and FoM = 2.616. At center frequency 2.65 GHz, the proposed LNA has S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> = -23.521 dB, S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> = 10.180 dB, NF = 2.776 dB, VSWR = 1.143, and FoM = 1.152. The center frequencies of fabricated proposed multiband LNA with MIT are shifted in average to 5-10 MHz lead to simulation results, and the performances of the fabricated of the proposed LNA with MIT are degraded about 7-10% by using Monte-Carlo Yield Analysis.