A Balanced LNA for L-band Radar Application

This paper presents design and development of an LNA based on balanced configuration for L-band radar application. Balanced configuration is the most suitable choice for concurrently meeting good matching, stability and linearity. Moreover, this configuration also offers inherent redundancy and added output power. In this scheme, the input and output couplers cancel out the reflections from the amplifiers and thus improve impedance matching. The bandwidth of balanced amplifier is dependent on both hybrid coupler and LNA's bandwidth. In this work, the targeted frequency band is from 1.0 to 2.0 GHz. The achieved gain is between 15 to 20 dB, noise figure is less than 2 dB and VSWR is less than 2.0 and output VSWR is less than 1.25. In the radar band i.e. 1.2 to 1.4 GHz, gain is 19 dB, noise figure is 1.1 dB and VSWR is less than 1.25.