A SAW-less LTE transmitter with high-linearity modulator using BPF-based I/Q summing

A SAW-filter-less LTE transmitter based on 65-nm CMOS technology, incorporating a passive quadrature modulator (QMOD) with band-pass-filter (BPF) I/Q summing technique, was developed. The passive operation and the BPF I/Q summing technique, respectively, contribute to low noise performance and high input impedance seen from baseband signal, resulting in low receiver-band noise and high linearity of the transmitter. A transmitter using the QMOD exhibits both inspecification receiver-band noise (<;-156 dBc/Hz) and high output 3^rd intercept point (OIP3 = 20.6 dBm).