Design of a Magnetically Tunable Low Noise Amplifier in 0.13 um CMOS Technology
With legacy technologies present and approaching new wireless standards, the 1-10 GHz band of frequencies is quickly becoming saturated. Although saturated, the frequency bands are being utilized inefficiently. Cognitive radio, an intelligent wireless communication system, is the novel solution for the efficient utilization of the frequency bands. Front-end receivers for cognitive radio will need the capability to receive and process multiple frequency bands and a key component is the low noise amplifier (LNA). A tunable LNA using a new magnetically tuned input impedance matching network is presented. The LNA has been designed and simulated in a commercially available 0.13 μm CMOS technology and is capable of tuning from 3.2 GHz to 4.6 GHz as S11 < -10 dB. Within this bandwidth the maximum power gain is 16.2 dB, the maximum noise figure is 7.5 dB, and the minimum IIP3 is -6.4 dBm. The total power consumption of the LNA (neglecting the buffer required to drive the 50 Ω test equipment) is 50 mW.
This tunable LNA introduces a new magnetically tunable matching technique and tuning scheme capable of continuous frequency variation for LNAs. It is expected that this technique could be expanded to realize LNAs with a tunable, narrow-band response that can cover the entire 1-10 GHz band of frequencies. The presented tunable LNA has demonstrated the capability to cover and process multiple frequencies and can be used for reconfigurable systems. A tunable LNA design is the first step in an effort to realize a fully reconfigurable front-end radio frequency (RF) receiver for future cognitive radio applications.