多端口接收机中的前端优化设计

发布时间：2018-01-20 03:44

本文关键词： 多端口前端六端口结补偿电容节数扩展　出处：《杭州电子科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着无线通信技术的快速发展,信息交换成为人类社会最基本的需求,各类无线通信产品在日常生活中越来越普及,它们将整个世界连成一个整体,为人类生活提供便利。在整个通信过程中,通信标准和信号占用的频带随着应用场景的不同也是各不相同的。为了有效传输信号,通信系统需要采用不同的调制方式,这就意味着需要不同硬件结构的接收机,硬件成本也会相应提高。将软件无线电技术(Software Defined Radio,SDR)应用于直接变频接收机能够对不同标准、频带以及调制方式的信号进行解调,在很大程度上降低了硬件结构和成本,当然也存在着一些问题,如自混频和I/Q支路失配等。将多端口技术应用到SDR接收机前端,不仅能够直接实现射频信号和基带信号之间的转换,省去混频器等高成本器件的使用,而且由于输入端口之间的隔离度较高还能在一定程度上消除自混频现象,因此多端口接收机受到了广泛的关注和研究。论文主要包括的内容有:1、阐述了多端口前端的相关理论,对二极管检波电路和加性传感过程进行了分析,并在此基础上分析推导了多端口传感网络的原理,重点分析计算了六端口技术的原理和信号解调过程,为后续多端口前端的优化设计提供了理论支撑。2、优化设计了组成多端口结的微波器件,包括一种频带范围为4~20GHz的四节椭圆威尔金森功分器,在单节窄带功分器的基础上,通过传输线的节数扩展和形状变换扩展了工作带宽,减小了传输损耗。还优化设计了两种3dB的宽带定向耦合器,一种是基于补偿电容技术的频带范围为2~8GHz的交叉串联耦合器,将各节耦合线不连续处产生的寄生阻抗效应降到了最低,有效提升了耦合器的性能;另一种为基于节数扩展和渐变形状的微带缝隙耦合器,将频带范围扩展为2~20GHz,提升了耦合器在宽频带内的性能。最后还从加工的角度分别对改进设计的功分器和耦合器进行容差性能分析,为后续加工提供一定的参考价值。3、从六端口结的带宽和性能方面着手,利用改进后的功分器和耦合器实现了两种六端口结的优化设计,一种为由宽带威尔金森功分器和改进的交叉串联耦合器组成的2.5~8GHz的宽带六端口结,通过节数扩展和补偿电容技术有效提升六端口结的整体性能,另一种为由宽带威尔金森功分器和缝隙耦合器组成的6~20GHz的宽带六端口结,通过节数扩展和形状变换有效提升了六端口的工作频带,最后经过仿真结果以及性能指标对比,验证了改进后的多端口结的性能。
[Abstract]:With the rapid development of wireless communication technology, information exchange has become the most basic needs of human society. All kinds of wireless communication products are becoming more and more popular in daily life, they will connect the whole world into a whole. In the whole communication process, the communication standard and the frequency band occupied by the signal are different with the application scenario. In order to transmit the signal effectively. Communication systems need different modulation methods, which means that different hardware structures are needed. The hardware cost will also increase accordingly. The application of Software Defined Radio SDRs to direct frequency conversion receivers can be applied to different standards. The demodulation of frequency band and modulation signal reduces the hardware structure and cost to a great extent, and there are some problems. Such as self-mixing and I / Q branch mismatch. The application of multi-port technology to the front end of SDR receiver can not only directly realize the conversion between RF signal and baseband signal, but also eliminate the use of high-cost devices such as mixer. And because of the high isolation between the input ports can eliminate the phenomenon of self-mixing to a certain extent, the multi-port receiver has received extensive attention and research. The main content of this paper includes: 1. The related theory of multi-port front-end is expounded, the diode detection circuit and additive sensing process are analyzed, and the principle of multi-port sensor network is analyzed and deduced. The principle of the six-port technology and the signal demodulation process are analyzed and calculated, which provides theoretical support for the optimization design of the follow-up multi-port front-end, and optimizes the design of the microwave device composed of the multi-port junction. It includes a four-section elliptical Wilkinson power divider with a frequency band range of 420 GHz. Based on the single-section narrow-band power divider, the bandwidth is extended by the section number expansion and shape transformation of the transmission line. The transmission loss is reduced. Two kinds of broadband directional couplers with 3dB are optimized. One is a cross-series coupler with a frequency band of 2GHz and 8GHz based on the compensation capacitance technology. The parasitic impedance effect caused by the discontinuity of each coupling line is reduced to the minimum, and the performance of coupler is improved effectively. The other is a microstrip slot coupler based on section number expansion and gradual shape, which extends the frequency band to 2o 20GHz. Finally, the tolerance performance of the improved power divider and coupler is analyzed from the point of view of machining, which provides a certain reference value for further processing. From the aspect of bandwidth and performance of six-port junction, the optimized design of two kinds of six-port junction is realized by using improved power divider and coupler. A broad band six-port junction consisting of a wideband Wilkinson splitter and an improved crossover series coupler is proposed to effectively improve the overall performance of the six-port junction by means of section expansion and compensation capacitance technology. The other is a 620GHz broadband six-port junction composed of a wideband Wilkinson splitter and a slot coupler, which effectively enhances the working band of the six-port by means of section expansion and shape transformation. Finally, the performance of the improved multiport junction is verified by the simulation results and performance comparison.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN851

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