Development of a High Efficiency OFDM Power Amplifier with a Pre-Distortion Circuit That Uses Temperature Compensation in the SHF Band

We developed a high efficiency power amplifier with a pre-distortion circuit that uses temperature compensation in the ISDB-T STL/TTL in the SHF band. This equipment works in the 7GHz band and greatly reduces distortions caused by non-linear characteristics of the amplifier by using a pre-distortion circuit. The amplifier consists of a pre-distorter, a power amplifier section, a control circuit for the temperature compensation and an ALC circuit to keep the output power constant. It maintains a great stability during temperature changes by controlling the input level of the pre-distorter according to the measured temperature in the power amplifier section. This amplifier has an excellent C/N ratio of 53 dB with an output of 2 W (OFDM average power) and a power efficiency of 2.2%.