Compact Wideband LNA With Gain and Input Matching Bandwidth Extensions by Transformer

This letter presents a compact wideband low-noise amplifier (LNA) with utilizing the transformers for gain and input matching bandwidth extensions based on the source degeneration topology. The wideband gain response is achieved by using a transformer gate-drain feedback technique to peak the gain at high frequency while the wideband input matching is obtained by employing a new transformer-based input matching network to produce two resonant points separately located at low and high frequencies within the operating band. Implemented in 65-nm CMOS process, the proposed LNA shows a measured peak gain of 10.2 dB with its 3-dB bandwidth ranging from 15.8 to 30.3 GHz and minimum noise figure of 3.3 dB. Taking advantage of the superior compactness from the transformer-based techniques, the LNA occupies very compact chip area of only 0.18 mm 2 , exhibiting as one of the most compact wideband LNAs.