A Tri-Mode Reconfigurable Receiver for GNSS/NB-IoT/BLE With 68-dB HR3 and 60-dB IMRR in 28-nm CMOS

In this article, a 0.7–2.5-GHz tri-mode reconfigurable receiver (RX) for global navigation satellite system (GNSS)/narrow band-Internet of Things (NB-IoT)/Bluetooth low energy (BLE) applications is realized targeting one chip capability of integrating both wide area network (WAN) and local area network (LAN) protocols as well as positioning characteristics in 28-nm CMOS process with a compact core area of 1.7 mm ² . By applying the proposed variable gain wideband active balun-low noise amplifier (LNA), the RX achieves minimum noise figure (NF) of 2.8 dB with the power consumption of 43 mW. The harmonic rejection (HR) method suppresses the signal interference caused by ON-chip coupling. 68-dB 3rd HR ratio (HR3) is achieved with only one-stage HR circuit. The mismatch between $I$ channel and $Q$ channel may limit the image rejection of the complex bandpass filter (CBPF). Detailed mathematical analysis of the $I/Q$ calibration circuit is provided. Owing to the virtual short characteristic of the amplifier, the $I/Q$ calibration scheme achieves a high-precision phase calibration. About 60-dB image rejection ratio (IMRR) is obtained after calibration.