Design and Analysis of a Continuously Tunable Low Noise Amplifier for Software Defined Radio

Aneja, A
Li, XJ
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Journal Article
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This paper presents the design and analysis of a continuously tunable low noise amplifier (LNA) with an operating frequency from 2.2 GHz to 2.8 GHz. Continuous tuning is achieved through a radio frequency impedance transformer network in the input matching stage. The proposed circuit consists of four stages, namely transformer stage, tuning stage, phase shifter and gain stage. Frequency tuning is controlled by varying output current through bias voltage of tuning stage. The circuit includes an active phase shifter in the feedback path of amplifier to shift the phase of the amplified signal. Phase shift is required to further achieve tunability through transformer. The LNA achieves a maximum simulated gain of 18 dB. The LNA attains a perfect impedance match across the tuning range with stable operation. In addition, it achieves a minimum noise figure of 1.4 dB.

Green radio; Software defined radio; Low noise amplifier; Transformer network; Tuning transistor; Phase shifter
Sensors, 19(6), 1273. doi:10.3390/s19061273
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© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (