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

本文提出了F类高效率微波放大器的电路综合方法，<th>在设计中考虑了高达7次的高次谐波频率。在F类微波放大器中，晶体管的负载阻抗在偶次谐波频率处为零，而在奇次谐波频率处为无穷大。异质结双极晶体管（HBT）由于基极-集电极等输出寄生电容的干扰，很难保持晶体管的开路状态。此外，F类负载电路中的电路损耗也降低了功率效率。在本计画中，利用ISE-TCAD二维元件模拟器，推导出F类放大器运作时，HBT集电区的最佳掺杂浓度。并引入tan δ=0.0023的低损耗树脂电路板，设计了考虑高达7次谐波频率的F类负载电路<th>，并在一台模具上进行了加工 关于我们 简化的电路形式。制造的InGaP/GaAs HBT F类放大器电路工作在1.9 GHz，提供74.2%的实测PAE（功率附加效率）和76.6%的实测集电极效率。在不考虑电路损耗的情况下，PAE为78.7%，集电极效率达到81.2%。这些值是工作在2GHz附近的微波放大器的基准结果。从3阶<rd>互调失真的角度来看，不仅要考虑基频，还要考虑谐波和次谐波频率，因为这些频率之间的混频现象对失真的产生具有重要作用。在FET F类放大器中，偶数阶高次谐波频率的短路条件带来较少的失真，因为经由偶数阶高次谐波频率的产生机制被删除。而在HBT F类放大器中，由于存在较大的基极-集电极电容，失真产生的机理比较复杂。指出了三阶互调失真信号在多个矢量之间存在自补偿<rd>现象。从次谐波频率终止条件的角度出发，在偏置供电网络处设置短路滤波电路，可以有效地降低双音信号和W-CDMA信号的失真。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