Research On Microwave Power Dividers With Various Performance And High-performance Power Amplifiers

With the rapid development of wireless communication techniques, devices in modern communication systems tend to have features with multi-model, miniaturization, higher integration level, and lower power consumption, which difficult the design of radio frequency devices indeed. In order to support the transmission of high speed signals and multiple communication protocols, the active or passive components in Microwave/radio frequency front-end systems are supposed to work with various and high performance. Due to the fact that power djvider and power amplifier are both key subsystems in wireless communication systems, the series of research work presented in this dissertation realize various performance power divider and high performance power amplifier, and the analysis is based on the basic transmission line theory. Several power dividers with novel structures are theoretically proposed and validated with experimental measurements, which support dual-band, harmonic suppression, and miniaturization. Besides, the power dividers can terminate with arbitrary complex impedances and offer arbitrary multi-way power distribution. For the research work in power amplifier, by means of reflection coefficient circle diagram, a geometric calculation method to solve the dual band complex impedance transformer is proposed. It shows the process of solving frequency dependence of the dual-frequency complex impedance to a pair of conjugate impedance by only one transmission line. Based on the solution of only one transmission line, the dual band power amplifier is successful designed. This paper also presents a novel dual band offset line structure, and it is used to implement dual-band Doherty power amplifier. The contributions are as follows:1. Two kinds of Wilkinson power divider with coupled line are proposed. These Wilkinson power dividers can be designed based on rigorous mathematical equations, and the proposed design theory is verified by simulation and measurement. The first kind is the dual band coupled line power divider with extended ports, and it is a generalized performance which can be simplified four special cases. Simulation and test verification focus on three new simplified cases, and the results show that performance is good and this structure can be applied to various occasions. The second kind is the single coupled line Wilkinson power divider with arbitrary complex terminated impedances, and it has a number of advantages, such as excellent bandwidth, miniaturization, reduce needs of additional impedance matching unit, and low cost.2. Four kinds of planar Bagley Polygon power dividers with new circuit structures and analytical design approaches are proposed. Equivalent circuit is set up respectively, design parameter equation is derived strictly, and design process is summarized in this paper according to different performance. Four kinds of planar Bagley Polygon power dividers are designed, implemented and verified by calculation, simulation and measurement. The first kind is the whole coupled line multi-way planar Bagley Polygon power divider, and it has a number of advantages, such as flexibility and miniaturization. The second kind is the multi-way planar Bagley Polygon power divider with arbitrary complex terminated impedances, and it has function of the simplified system. The third kind is the miniaturization of3-way planar Bagley Polygon power divider with dual transmission lines, and the power divider greatly to realize the miniaturization with only23%circuit size of the conventional one. The forth kind is the multi-way planar power divider with enhanced harmonic suppression. For verification, a3-way and5-way Bagley Polygon power dividers are fabricated and measured to show the single harmonic suppression and enhanced harmonic suppression, respectively. In the final experiment, excellent measured performance can be observed.3. Study on a novel calculation method of dual band complex impedance transformer, and successful design a dual band power amplifier. Based on the Smith chart, a geometric calculation method to solve the dual band complex impedance transformer is proposed. Through the parameters detailed derive, the process of solving frequency dependence of the dual-frequency complex impedance to a pair of conjugate impedance by only one transmission line is shown. And through the circuit simulation, electromagnetic simulation and measurement triple methods were verified. Based on the solution of the only one transmission line and the combination of the π type structure for dual band impedance matching, the dual band power amplifier worked at0.9GHz/2.14GHz simultaneously is successfully designed. Results show that there is an excellent measured performance.4. A novel dual band offset line is presented. And based on this offset line, a dual band Doherty power amplifier is successfully designed. This paper proposes a novel dual band offset line, and the design equations are strictly derived according to the structural characteristics. For verification, a proposed dual band offset line is fabricated, measured and electromagnetic simulated. Based on the dual band power amplifier designed in this article earlier, and combined with the proposed dual band offset line, the dual band Doherty power amplifier worked at0.9GHz/2.14GHz simultaneously is successfully designed. And the dual band power amplifier with excellent performance has been simulated and measured.