A Fully Polar Transmitter for Efficient Software-Defined Radios
While polar modulation is a transmitter technique that is known to maximize energy efficiency, it also has no circuit linearity and traditionally is unable to produce signals that contain envelope zeros such as QAM and LTE. This polar transmitter solves this weakness and is modulation agnostic across the decade-wide tuning bandwidth of 200 – 2500 MHz. In particular, a conventional Nyquist filtered 256QAM signal is generated with error vector magnitude (EVM) less than 1.5% across the frequency range, and is below 1% across the bottom decade of frequency – without use of digital predistortion (DPD) linearization. Peak output power is 2.5 watts.