An In-Band Full-Duplex Low Noise Amplifier Integrated With an Electrical Balance Duplexer Without Explicit Matching

Abstract

This letter presents a low noise amplifier (LNA) integrated with an electrical-balance duplexer (EBD) for in-band full duplex operation in a 65-nm bulk CMOS process. A simultaneous noise and input matching (SNIM) structure consisting of a large transistor and hybrid transformer for EBD is proposed. The proposed structure does not require an additional matching circuit between the LNA and the antenna (ANT). Furthermore, the use of a large transistor in the SNIM helps minimize the noise figure (NF). The core size of this LNA is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.86\times0.33$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The measurement results show 14.6–16.5 dB ANT-RX (receiver) gain, 4.29–4.53 dB TX-ANT loss, 30.6–34.5 dB isolation, and 5.33–5.37 dB NF. The LNA has an input 1-dB compression point (IP1dB) of −18.1 dBm at 15 GHz and the power consumption is 22 mW.