Generation Mechanism for 3^<rd> Order Inter-Modulation Distortion in Harmonic Frequency Controlled Ultra-High Efficiency Amplifier

提出了F类高效率微波放大器的电路综合方法，在设计中考虑了高达7阶的高次谐波频率。在F类微波放大器中，晶体管的负载阻抗在偶数次谐波频率时为零，在奇数次谐波频率时为无穷大。在异质结双极晶体管(HBT)中，由于输出寄生电容(如基极-集电极电容)的干扰，晶体管的开路条件很难保持。此外，F类负载电路中的电路损耗也会降低电源效率。在本项目中，利用ISE-TCAD二维器件模拟器，推导出了F类放大器工作时HBT集电极的最佳掺杂浓度。并引入了tanδ=0.0023的低损耗树脂电路板，在di…中设计并制作了F类负载电路，最高可达7次谐波更具条纹状的电路形式。制作了工作在1.9 GHz的InGaP/GaAsHBT F类放大电路，获得了74.2%的测量功率附加效率和76.6%的测量集电极效率。在去嵌入电路损耗的情况下，PAE为78.7%，集电极效率达到81.2%。这些值是在2 GHz左右工作的微波放大器的基准结果。在3阶互调失真观点中，不仅应该考虑基波频率，而且应该考虑谐波和亚谐频率，因为这些频率之间的混频现象对失真的产生起着重要的作用。在场效应管F类放大器中，由于去掉了偶数阶高次谐波的产生机制，偶数阶高次谐波的短路条件带来的失真较小。然而，在HBT F类放大器中，由于存在较大的基极对集电极电容，失真的产生机理较为复杂。指出了3阶互调失真信号存在多个矢量之间的自补偿现象。从亚谐频率终止条件的角度来看，偏置电源网络上的短路滤波电路对于减小双音和W-CDMA信号的失真都是有效的。较少

Circuit synthesis methods for class-F high efficiency microwave amplifiers have been proposed, where up to 7^<th> order higher harmonic frequencies are taken into consideration in the design. In the class-F microwave amplifiers, load impedances for a transistor are zero at even order harmonic frequencies and those are infinity at odd order harmonic frequencies. Because of intervention of output parasitic capacitance such as base-collector capacitance in heterojunction bipolar transistors(HBT), the open circuit condition for the transistor is difficult to be retained. In addition, circuit losses in class-F load circuit degrade power efficiency also. In this project, using the ISE-TCAD two dimentional device simulator, optimum doping density for HBT collector has been derived for the class-F amplifier operation. And also introducing low loss resin circuit board with tan δ=0.0023, class F load circuit considering up to 7^<th> order harmonic frequencies were designed and fabricated in a di … More stributed circuit form. Fabricated InGaP/GaAs HBT class-F amplifier circuits operating at 1.9 GHz delivered 74.2% measured PAE(Power Added Efficiency) and 76.6% measured collector efficiency. In the case that circuit loss is de-embedded, the PAE is 78.7% and the collector efficiency reached 81.2%. These values are bench mark results in microwave amplifiers operating around 2 GHz.In a 3^<rd> order inter modulation distortion view point, not only a fundamental frequency, but also harmonic and sub-harmonic frequencies should be taken into account, since frequency mixing phenomena among these frequencies take important rolls for distortion generations. In FET class-F amplifier, short-circuited conditions for even order higher harmonic frequencies bring about less distortions, since generation mechanism via even order higher harmonic frequencies are deleted. However in the HBT class-F amplifiers, because of existence of large base to collector capacitance, the distortion generation mechanism are more complicated. It has been pointed out that self compensation among multi vectors for 3^<rd> order inter-modulation distortion signals occurs. In a view point of sub-harmonic frequency termination conditions, short circuited filtering circuits at bias supplying networks are found to be effective to reduce the distortions for both two tones and W-CDMA signals. Less