500MHz--3000MHz中频放大电路设计
毕业论文关键词：功率放大器；GaAs HBT；自适应线性偏置电路；RC 并联稳定网络 Abstract The design of amplifier is based on GaAs HBT process technology, achieved the targets of high power gain, high output power and high efficient, with two-stage structure. In this paper, the key issues of power amplifier design are analyzed, and some effective solutions have been proposed. The adaptive linear bias circuit is designed for providing offset-voltage to the transistor, at the meantime, the reducing base-emitter voltage of the power tube due to the high power input is compensated, the amplifier's offset point is also maintained constant, and the phenomenon of gain compression is inhibited. In addition, the temperature drift phenomenon of the DC bias point and the current gain collapse phenomenon due to the self-heating effects is effectively inhibited by the temperature compensation circuit in the bias network using the thermoelectric negative feedback characteristics of HBT power devices. Through adding a RC parallel stable network in the base of each power tube, the potential instability of the transistor are eliminated, and the electrical and thermal stability of the circuit is improved. The maximum gain is realized by conjugate matching the first-stage power amplifier, the power matching principle is adopted according to the maximum output power design of the last stage amplifier power. Ultimately, the parasitic effect is considered sufficiently during the layout designing and PCB testing. The testing results of two-stage GaAs HBT power amplifier chip after the PCB commissioning show that the power gain of amplifier is 50.6 dB in the small signal, the specification requirements of design is successful implemented.
Key words: GaAs HBT; self-adaptation linear bias circuit; base stability resistor; RC parallel stable network
目录
摘 要 .. 1
Abstract . 2
第 1 章 绪 论 5
1.1 MMIC 功率放大器的发展前景 .. 5
1.2 GaAs HBT 功率器件的发展 .. 6
1.3 本论文的研究意义和主要内容 .. 7
第 2 章 MMIC 功率放大器设计技术及关键问题分析 .. 8
2.1 器件形式的选择 8
2.2 HBT 器件的工作原理 9
2.3 衬底材料的选择 . 10
2.4 MMIC 功率放大器的效率模式 11
2.5 MMIC 功率放大器的设计方法 13
2.5.1 小信号 S 参数设计法 14
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