应用于WLAN的高效率F类功率放大器

为了提高在高速率信号传输下无线通讯发射系统中功率放大器的工作效率,提出了一种结构新颖的高效率F类功率放大器.通过计算机仿真与实验板调试相结合的方法确定了放大器的最佳漏极阻抗,根据F类放大器漏极电压和漏极电流是相位差为λ/4的方波和半正弦波的特性,通过仿真软件设计和优化,设计出的谐波滤波网络在输出谐波频点有良好的滤波性能.为了降低栅源电容对输入信号造成的失真,在输入端口加入短截线,提高了放大器的漏极效率.通过测试,功率放大器工作在2.4GHz时,在2dB增益压缩点的功率附加效率为67%,输出功率为30dBm.测试结果表明,该高效率功率放大器适合应用于WLAN无线通讯发射系统.

High efficiency class-F power amplifier for WLAN applications

A novel class-F power amplifier is designed for high-speed radio frequency (RF) transmitters to increase the efficiency of wireless communication systems.A method combining computer simulation with experiment test is used in decision of the optimal drain impedance of the transistor.For class-F power amplifier,the waveforms of drain voltage and drain current are square and half-sinusoidal respectively with a phase difference of λ/4.According to the characteristics,using Agilent advanced design system(ADS),simulation is performed to design harmonic filter circuit.The simulation results show that the filter circuit has a good performance at the frequency of the second and third harmonics.A stub paralleled with the gate is applied to avoid nonlinear distortion at the input port due to gate-source capacitance.The experimental results show that the amplifier works at 2.4GHz with the power-added efficiency of 67% and the output power of 30dBm.Comparison and analysis show that the presented power amplifier provides a good performance and is excellently suitable for wireless local area network (WLAN) applications.