I/Q Balance-Enhanced Wideband Receiver Front-End for 2G/3G/4G/5G NR Cellular Applications

In this paper, an in-phase (I) and quadrature-phase (Q) balance-enhanced wideband receiver RF front-end is proposed using a quadrature sampling passive mixer configuration, which can be applicable to 2G/3G/4G/5G new radio (NR) applications. Compensating mixer switches are additionally utilized in parallel with main mixer switches in a quadrature mixer for quadrature downconversion. As a consequence, gain and phase errors from the mixer can be mutually compensated at the mixer output, and I/Q imbalance characteristics are significantly improved without an extra calibration process. For the verification of I/Q balancing improvement, the receiver front-end is implemented, which consists of a wideband low noise transconductance amplifier, a double-balanced quadrature sampling passive mixer, transimpedance amplifiers, and quadrature local oscillator signal circuitry. The demonstrated design is fabricated in a 65-nm CMOS process and mainly characterized in long-term evolution (LTE) frequency bands. The implemented design achieves an error-vector magnitude of less than 2% with conversion gains and noise figures of more than 41 dB and less than 4.7 dB for all frequency bands, respectively. Moreover, the design attains in-band and out-of-band IIP3s of higher than -12 dBm and -2.7 dBm for LTE frequency division duplexing test conditions, respectively. The active die area of the implemented receiver front-end is 0.72 mm
²
. It draws a bias current of 18.2 mA from a nominal supply voltage of 1.2 V.