RF predistortion of power amplifiers using 2/sup nd/ harmonic based technique for optimization of intermodulation products

An RF predistortion linearizer using a combination of a second harmonic and a difference frequency technique is proposed to reduce 3/sup rd/ and 5/sup th/ order intermodulation products in high power amplifiers. The second harmonic and difference frequency terms are generated using an envelope detector and two frequency multipliers. The RF predistorter has the advantage of low insertion loss and a short delay line requirement. From the experimental results, adjacent channel power ratio (ACPR) reduction of 11 dB is achieved for W-CDMA at 2140 MHz.