Gain-controlled noise-reduction LNA design using source-bulk resistors and double common-source topology

摘要

This paper presents the design of a Low Noise Amplifier (LNA) using double common-source technique results in wideband input matching. Moreover, to reduce the noise figure, a resistor series to source-bulk substrate resistance is applied. One of the main problems of the common-source structure in LNA design is the narrow-band property. Using the proposed double common-source scheme, the narrow-band problem is solved and the desired wideband attributes can be achieved. In addition, using a resistor series to the source-bulk substrate resistance results in significant noise figure reduction. In the proposed scheme, the gain of LNA in frequency band of 3-12 GHz would be between 14.2 dB and 15.1 dB. Furthermore, the variation of gain in this band is 0.45 dB which is significant. The 3-dB bandwidth of the designed LNA is 10.2 GHz (from 2.4 to 12.6 GHz). The worst case of return loss of input port is -10 dB. The above mentioned series resistor causes the noise figure to decrease and set between 3.47 and 4.12 dB. Using 180-nm TSMC technology, the DC power is 11 mW from 1-V supporting voltage.