A highly linear broadband LNA for TV white spaces and Cognitive Radio applications

Communications in the TV White Spaces are gaining increasing interest due to the crowded frequency spectrum and rising demand for higher data rates. Especially the dynamic access by Cognitive Radios is under research, offering a more efficient usage of the spectrum. Due to the broadband nature of Cognitive Radio systems and the presence of numerous strong interfering signals, the expectations on the linearity of such systems are extremely hard. In this paper, an integrated CMOS broadband highly linear fully differential LNA is presented, which enables a receive path to fulfill the hard linearity requirements for broadband cognitive TV White Space applications. The proposed LNA has a bandwidth of 300MHz to 1 GHz and works without any external components. It utilizes Complementary Derivative Superposition to cancel third order intermodulation products and has an IIP₃ of 19 dBm, CP_1dB of -3dBm and Noise Figure of 2.6 dB within the TV White Space 470 MHz-790 MHz, while consuming 4.8mA from a 3.3V source.