【作者】 李焱明；

【导师】 李勇；

【作者基本信息】 西安电子科技大学 ， 电磁场与微波技术， 2010， 硕士

【摘要】 在近场天线测量中,单探头进行机械扫描需要耗费大量时间,难以达到快速测量天线的目的;基于调制散射技术的近场天线测量,能较好的解决天线测量过程中的精确度问题。本文首先介绍了天线测量技术的发展以及调制散射近场天线测量的原理,在讨论了如何实现天线快速测量的情况下,提出一种实现天线快速测量的方法。天线快速测量系统采用阵列天线作为接收探头以减少机械扫描的时间,将接收到的信号通过微波电路进行调制后送入接收机,从而实现天线的快速测量。探头阵列中的阵元采用双极化印刷振子,印刷振子结构简单、易于制作。振子在天线测量系统中作为接收天线使用,应具有尽可能宽的带宽。文中介绍了一些微带天线频带展宽技术,分析设计了宽频带单极化印刷振子天线,在此基础上设计出双极化印刷振子。探头阵列是由四个双极化印刷振子构成的直线阵,需对振子间距进行优化,以减小阵元之间的互耦。探头阵列能同时接收不同位置上的两个极化方向的数据,为了便于接收机进行处理,对微波信号进行调制,使其依次进入网络分析仪中。调制电路采用微波开关芯片,输入TTL信号作为控制信号对微波信号进行调制。由于有多路信号进入接收机,用一个一分八Wilkinson功分器将调制电路输出端口与接收机相连。功分器采用了微带线结构,阻抗变换线采用圆弧过度的形式。圆弧过度可以降低输入口的驻波,展宽功分器的频带以及减少互耦的影响。更多还原

【Abstract】 In the near-field antenna measurement, the time required by the single probe mechanical scanning becomes prohibitively long. The near-field measurement system based on the modulation scattering technique can improve precision of measurement. In this paper, development of near-field antenna measurement and basic theory of modulated scatter near-field measurement are introduced. After researching on how to fast measure antenna, a method of fast measurement antenna is proposed. The fast measurement antenna system use probe array to mechanical scan, signals received by probes are modulated by microwave circuits, and modulated signals are sent to receiver.Dual-polarized printed dipole as the element of probe array. Printed dipole has the merits of simple structure and easy production. Dipole is used as received antenna in the measurement system, so it should have ultra wide band. This paper introduces the broadband technology of microstrip antenna and analyzes the single-polarized printed dipole. On this basis, a dual-polarization printed dipole is designed. Probe array is a linear array, which elements are four dual-polarized printed dipoles. The distance of dipole is optimized in order to reduce the impact of mutual coupling between elements.Probe array can receive many signals from each element. Microwave signals are modulated and sent to network analyzer in sequence. Modulated circuits use microwave switch chip, and TTL imported as modulation signal. Because many channel signals are imported to receiver, a one-eight Wilkinson power divider was used to connect circuits and analyzer. The power divider use microstrip line structure and impedance transformation line uses the form of arc. The form of arc can reduce the input VSWR, broaden the working band and decrease the impact of mutual coupling.更多还原