듀얼 주파수 체배기를 이용한 전치왜곡 선형화기 설계 및 제작

In this thesis,a predistortion linearizer was designed and fabricated with a dual frequency multiplier empolying harmonic injection method for high power amplifier in CDMA repeater. To supress the spectral regrowth in the adjacent channels effectively, the odd order intermodulation distortions should be cancelled. For the purpose, the predistorter, which can cancel the 3rd and 5th intermodulation distortions independently, has been implemented. The predistortion linearizer used a dual frequency multiplier to minimize size and DC current. The implemented predistorter linearized the RF power amplifier with average power 40dBm at 870~880MHz band. The predistortion linearizer was improved by 22dB IMD(intermodulation distortion) at 2-tone signals(37dBm/tone) and 6.8dB ACPR(Adjacent Channel Power Ratio) at 1FA CDMA source signals from 1.98MHz offset. By applying this predistorter to amplifier, PAE(Power Added Efficiency) performance of power amplifier was improved by 7% under same ACPR specification.