S波段40 W GaN高效率内匹配功率放大器的设计

Design of an S-band 40 W GaN high efficiency internally matched power amplifier

功率放大器在饱和工作状态下可以达到很高的效率,但在饱和工作状态下,谐波(主要是二次谐波)会明显降低功率放大器的效率。合适的谐波控制电路可以提高功率放大器的效率。采用谐波控制的方法,设计并实现了一种S波段40W GaN高效率内匹配功率放大器。在设计过程中,器件选用0. 5μm工艺GaN HEM T管芯,采用一个较小的电感L和一个较大的电容C使得二次谐波短接到地,并利用一级低通LC电路将阻抗匹配到目标阻抗50Ω。测试结果表明,放大器在工作频率范围3. 1～3. 4 GHz内,在漏电压48 V,占空比10%,脉宽0. 1 ms的条件下,输出功率大于46. 8 d Bm(48.3 W),最大输出功率为47. 4 d Bm(55.3 W),带内饱和功率增益大于10 dB,漏极效率大于63. 8%,最大漏极效率达到73. 9%。

A power amplifier on the saturated operation can be highly efficient. However, the harmonics reduce the efficiencyof a power amplifier on the saturated operation, mainly the second harmonic. Therefore, a S-band power amplifier using a 0. 5 μmGaN HEMT was designed and realized based on the harmonic control circuit. A small inductance and a large capacitor were used tomake the second harmonic short, and an L-C low pass matching network was used to realize the matching to systemic referenceimpedance of 50 Ω within the giving band. The test results show that the power amplifier exhibits an output power more than 46. 8dBm with a maximum of 47. 4 dBm, a power gain over 10 dB, and a drain efficiency over 63. 8% with a maximum of 73. 9% acrossthe band of 3. 1-3. 4 GHz, and at drain bias voltage of 48 V and input pulse width of 1 ms with a duty cycle of 10%.