毫米波宽带谐波混频器

【作者】 白锐；

【导师】 徐军；

【作者基本信息】 电子科技大学 ， 无线电物理， 2008， 硕士

【摘要】 在毫米波系统中,性能优越的谐波混频组件,不仅对系统性能起着关键性作用,同时也可以降低信号源的成本,提高系统的集成密度。随着现今应用频段的提高和频带范围的加宽,宽带谐波混频器的应用得到了越来越多的重视。本文对毫米波宽带谐波混频器进行了研究,并分别设计了U频段和V频段的宽带谐波混频组件。此次的工作是应用户需要,设计U频段和V频段的宽带接收组件,本文主要承担谐波混频器的研制工作。要求在U和V全频段内,实现宽带变频性能,变频损耗分别小于17dB和20dB,各端口隔离度要求大于20dB。根据指标要求和实际条件,本文把本振信号频率设计为射频信号频率的1/4,输入功率为5dBm,经过二次频率倍增和功率放大后,再在鳍线电路上实现二次谐波混频。根据以上设计思路,本文采用反向并联二极管对(DMK2308),来实现二次谐波混频;使用单片射频微波集成电路(MMIC)实现频率倍增和功率放大;利用鳍线电路结构,来实现宽带混频电路。文中首先对谐波混频器进行了介绍,分析和阐述了谐波混频的特性和技术要求。其次对宽带谐波混频器的实现进行了分析和设计,提出两种可行和参考的设计方案。再者,对鳍线电路特性和不同鳍线结构进行了研究和实验,针对不同的鳍线结构,分别设计了双侧鳍线谐波混频器、单侧鳍线谐波混频器和单脊鳍线谐波混频器。并对其中的过渡电路、匹配电路和信号回路结构等进行了设计与分析。为了满足系统小型化和集成化的要求,本文设计了新颖的微带-鳍线过渡模型,实现微带电路与鳍线电路的集成应用。根据不同的鳍线结构,分别对应设计了微带-单侧鳍线过渡、微带-双侧鳍线过渡和微带-单脊鳍线过渡模型。对过渡特性进行了理论分析与讨论,并加工了实验样品进行测试验证。本文最终采用双侧鳍线谐波混频电路作为用户产品。测试结果表明,在所要求的整个频段范围内,双侧鳍线谐波混频器具有很好的宽带谐波混频特性,变频损耗、隔离度和稳定性等指标均满足用户工程上的要求。同时,对单侧鳍线和单脊鳍线谐波混频器也进行了研制和测试,这两种电路结构也可实现较好的宽带混频器特性,并具有一些不同的应用特点。最后根据测试结果,对影响混频器性能的因素进行分析和讨论,并提出了一些改进措施和完善方案。作为毫米波接收系统的重要部件,宽带谐波混频器不论在军事领域还是民用领域都会得到更多的发展和应用。本文研制的宽带鳍线谐波混频器,可以对今后的研究和设计工作提供一定的参考价值。更多还原

【Abstract】 In the Millimeter-wave system, the sub-harmonic mixer with excellent performance not only plays a key role in system, but also reduces the cost of signal source and increase the density of integrated system. More and more attention has been paid on the application of the wide-band sub-harmonic mixer with the improvement of the frequency and the bandwidth nowadays. This dissertation makes a research of the wide-band sub-harmonic mixer and designs the sub-harmonic mixer module for the U-band and V-band respectively.The major task is manufacturing two wide-band receiver front-end both in U-band and V-band for the user’s requirement. This paper mainly embodies the research part of the sub-harmonic mixer. An excellent mixing performance has to be realized at full frequency band. The conversion loss is required below the 17dB and 20dB respectively, and the isolations are nearly higher than 25dB between every port.According to the requirement and the practical condition, the LO signal input frequency is designed as 1/4 part of the RF frequency, and the input power is 5dBm. Then it is multiplied two times and amplified for power. This paper adopts a pair of anti-parallel diodes (DMK2308) to realize sub-harmonic mixing, and adopts the Monolithic Microwave Integrated Circuits (MMIC) to realize the frequency’s multiplication and the power’s amplification. The finline circuit realizes the wide-band sub-harmonic mixer circuit.This dissertation introduces the sub-harmonic mixer firstly. It analyses and illustrates the characteristic and technical specification of sub-harmonic mixer. Secondly, it presents and designs the realization method of wide-band sub-harmonic mixer in order to suggest several design plans of feasibility and possibility. Thirdly, it has made some research and experiment both on the characteristic of finline circuit and the different structures of finline. It designs the unilateral finline, the bilateral finline and single ridge finline sub-harmonic mixers according to the different structures of finline. Finally, in the light of finline structure’s features, it also designs and analyses on the transition structure, match circuit and signal return circuit. In this paper, a new kind of microstrip-to-finline transition model is developed in order to achieve the aim of integrated application both the microstrip circuit and finline circuit. It can make the system easy to be miniaturized and integrated. In response to different structure of the finline, we design the microstrip-to-unilateral finline, the bilateral finline and single ridge finline transitions respectively. It theoretically analyses and discusses on the feature of transition model. At the same time, an experimental sample is manufactured for test.This paper adopts ultimately the as the user’s product. The testing result indicates that the bilateral finline sub-harmonic mixer has a good performance of the wide-band mixing. All test results can meet the demand of the user’s project such as the conversion loss, the isolation and the stability etc. In the meanwhile, the unilateral finline and single ridge finline sub-harmonic mixers are also manufactured for study. A good characteristic of wide-band mixer can be realized in both these two kinds of circuit structures and also get some different application features. Finally, we discuss and analyze on the factors which influences the module performance according to the testing result. We suggest some measures and plans for improvement and perfect.As the important component of receiver system in Millimeter-wave, wide-band sub-harmonic mixer has an obvious role. Its prospect and application are widespread applied in civilian or military region. This assignment design of wide-band sub-harmonic mixer may be a practical reference for study and development in future.更多还原