부산대학교 도서관

Recently, there is an increasing demand for better in-band(IB) and out-of-band(OOB) linearity for sub-6GHz applications [1 – 3]. To achieve high linearity, one solution is to utilize current-mode direct conversion [1]. In this architecture, the low-noise amplifier (LNA) acts as a transconductor, which avoids large voltage gain, thus achieving high linearity. Another solution is to employ mixer-first architecture [2,3]. This kind of receiver starts with a passive mixer, which avoids any possible voltage gain brought by the LNA and shows improved tolerance to the blockers. However, unlike the current-mode architecture, its transimpedance-amplifier (TIA) input is not a virtual ground, but a high-impedance node, for input matching purpose [2]. Meanwhile, to achieve better NF, noise-cancellation techniques are widely used in different architectures to improve the noise performance [4,5], achieving sub-1dB NF at 1GHz [4] and 1.75dB NF at 5GHz [5]. However, both receivers are with LNA-first architecture, which limits their linearity.