Research And Implement Of The Gan Class-F Power Amplifier

As the wireless communication systems are intended to high speed and high data-rate, the modulated signals have higher peak-to-average power ratios (PAPRs). Therefore, power amplifier needs to satisfy the linearity of the system by back-off method. So how to improve the efficiency at low power level becomes a hot issue for wireless communication systems.In order to solve this problem, it is researched a class-F power amplifier. In a class F power amplifier, it is accomplished by harmonic control circuit (HCC) in output network that either zero or infinite impedance at even or odd harmonics frequencies. The drain current waveform and voltage waveform are half-sinusoid and square-wave, respectively.1)The class F simulations using CGH27030F are accomplished by using Advanced Design System (ADS2009). At2.65GHz, the amplifier has peak drain efficiency (DE) of88%with an output power of44.8dBm. It is simulated that S11is smaller than-10dB during the bandwidth between2.6GHz and2.7GHz. S21is bigger than15dB and smaller than16dB.2) The design was fabricated on ROGERS4350B with relative dielectric constant of3.48and substrate thickness of30mil. It is measured that S11is smaller than-10dB during the bandwidth between2.55GHz and2.75GHz. S21is bigger than13dB and smaller than14dB. the peak output power is44.7dBm, meanwhile the drain efficiency is more than90%, and there is also a drain efficiency of41%with an average output power of36.2dBm. When the output power was about35.2dBm (average output power) the ACPR is-30dBc used a2.65GHz2-carrier WCDMA signal. After DPD, the ACPR is-47dBc. 3) The basic principles of Doherty amplifier are introduced in section4. Using class-F amplifier as a unit in Doherty PA, a design of class-F Doherty amplifier is accomplished with ADS. It operates during2.6GHz to2.7GHz. At2.65GHz, the amplifier has an output power of47dBm. It still has a drain efficiency of42%with an a output power of38dBm. Among them, several factors that affect the performance of the Doherty amplifier have been analyzed.