Self-Powered Balun Low Noise Amplifier with Degeneration Balancing and Thermal Noise Analysis

Abstract

The Balun low noise amplifier (LNA) is an LNA that exploits a combination of a common-source (CS) and a common-gate (CG) transistor, which cancels the noise and distortion of the CG stage. And since the CG is known to be linear, only the CS needs to be carefully designed and optimized. In this thesis, the CS section will be fully analyzed, and shown how the condition set in the literature review still satisfies the balancing output and cancels the CS stage thermal noise as well as the CG thermal noise. Also, forward body biasing (FBB) is used to reduce the threshold voltage and in addition, CS degeneration resistor will be studied to balance the output and cancel the thermal noise of the transistors. The circuit is tested using UMC180nm on Cadence. The LNA achieves a gain of 19-16dB, NF<3.6 dB over the bandwidth 0.2-1.9GHz without a CS degeneration. A 17.8-14.8dB gain, a NF<3.8 dB over the bandwidth 0.2- 2.1GHz and power consumption of 12mW in both cases. Although outside the bandwidth, at ISM 2.4GHz a gain of 14.5dB and a NF of 3.8 is achieved, making it suitable for wireless sensor node (WSN) applications. According to the authors’ knowledge, this is the first time the degeneration resistor noise analysis on a Balun LNA is derived and simulated. Also, an RF harvester will be studied and used to power the Balun LNA. A two stage Dickson charge pump using MOSFET connected diode is chosen for this application. Although the efficiency is around 40%, the harvester was successfully integrated to the LNA, and its noise figure added to the output of the LNA.