A 3-6-GHz Highly Linear I-Channel Receiver with over +3.0-dBm In-Band P_1dB and 200-MHz Baseband Bandwidth Suitable for 5G Wireless and Cognitive Radio Applications

A highly linear I-channel receiver prototype is presented for a 3-6-GHz broadband radio system with a 200-MHz baseband bandwidth and verified to operate under congested spectrum environments. A direct conversion receiver developed from this prototype is suitable for a cognitive radio, a fifth-generation (5G) receiver, and other wireless systems with a total (in-band signal plus blocker) power of above -6.0 dBm. The broadband receiver consists of a low-noise transconductance amplifier (LNTA), a passive mixer, a wideband transimpedance amplifier, and a power-efficient minimally invasive baseband filter. The LNTA with high linearity employs a cross-coupled structure and resistive degeneration to achieve low noise and high linearity simultaneously. The common-gate-based LNTA achieves 2.3-dB noise figure in simulation. Fabricated in a mainstream 40-nm CMOS technology, the worst case measured system noise figure is under 5.8 dB at 3-MHz baseband frequency, and the conversion gain is larger than 12.8 dB with passband variations under 2 dB from 1- up to 200-MHz signal bandwidth. Over 3-6 GHz, the receiver's in-band input third-order intercept point (IIP3) and input P_1db are higher than 15.1 and 3.0 dBm, respectively, whereas the power consumption varies from 64.1 to 69.6 mW.