A Compact 11–27.3 GHz CMOS LNA Employing a 5-in-1 Transformer Feedback for Wideband Operation

This work presents a compact wideband LNA employing a five-in-one transformer that integrates a source-degeneration LNA with shunt–series feedback (SD-SSF) and a drain-to-gate transformer feedback path combined with a coupling-tuned resonant tank (CTRT). The design reduces the number of active stages through current reuse, lowering chip area and power consumption while maintaining broadband gain and low noise. Implemented in 65-nm CMOS, the LNA achieves a peak gain of 13.8 dB from 11 to 27.3 GHz, with an in-band noise figure (NF) of 2.5–4.5 dB and a minimum NF of 2.5 dB. The circuit occupies a 0.13 mm² core area and consumes 8 mW, demonstrating efficient wideband performance with reduced size and power.