Highly reconfigurable single-ended low noise amplifier for software defined radio applications

A reconfigurable low noise amplifier with variable gain, bandwidth and center frequency is described. In order to achieve this degree of reconfigurability, this amplifier employs variable-bias active shunt feedback input matching, with a switchable capacitive load and a Q-enhancing negative g_m circuit in parallel with the load. This design also features a noise cancelling technique, which helps to eliminate noise contributions from the primary gain FETs and simultaneously enhance the gain. This design was built on IBM´s CMOS 0.13μm process through MOSIS and was designed for a 1.2V supply. This LNA has a min-to-max 3dB bandwidth ratio of approximately 3.1 while achieving a noise figure as low as 2.5dB, less than -10dB return loss, and IIP3 as high as -0.9dBm at low gain.