A Wideband Multilevel Reconfigurable Class E/F23 Power Amplifier With a Band-Selecting Tracking Reactance Compensation Automatic Calibration Algorithm

This paper presents a wide-band multi-level switched mode class-E/F
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Power Amplifier (PA) with a reconfigurable power stage core transistor and a load with reconfigurable reactance compensation part. An Automatic Calibration Scheme (ACS) is proposed to perform the core and load reconfiguration based on a proposed algorithm. The PA is formed by a class-D driver amplifier, the switched mode cascaded reconfigurable power stage, the reconfigurable class-E/F23 load, the ACS and its algorithm, and the matching network at the end of the load before the antenna. The proposed PA is implemented using a 130 nm CMOS technology. The wideband PA operates in the frequency range from 470 MHz to 690 MHz for a TV White Space (TVWS) application with 220 MHz bandwidth. Even though reaching a high maximum Power Added Efficiency (PAEmax) for the design with low output powers is challenging a PAEmax of 32% for a 10 dBm output power level from a low supply voltage of 2.2 V. The proposed ACS provides an output power with a flatness around 0.6 dB which shows 57% improvement in compare with the structure without the ACS. The PA achieved a selectable multi-level output power from 10 dBm to 14 dBm over the 220 MHz bandwidth.