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Adaptive microwave front ends for wireless communications.

机译：用于无线通信的自适应微波前端。

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摘要

This dissertation introduces several new architectures used in microwave adaptive front ends. The need for adaptive system hardware in wireless communication systems is being driven by several factors such as performance and budget. In order to improve both performance and system cost, the receiver and transmitter in a wireless system may be controlled adaptively.; The first type of system examined is a new smart antenna array receiver with adaptive beamforming. The novel system offers a drastic reduction in hardware requirements for the smart antenna system through the use of a new Spatial MultIplexing of Local Elements (SMILE) scheme. In this scheme a single element of the array is sequentially connected to signal processing circuitry in order to sample the incoming modulated carrier. The sampling rate is chosen so the information of the original signal can be fully restored in the post stages. This system offers an N times reduction in hardware for an N element array. System principles, SNR, advantages, and hardware, including a new type of array feed network, are discussed. The system performance is validated through a link test with digitally modulated data.; RF radiation performance of the antenna array is of concern and so is investigated. A new method for reducing mutual coupling in a SMILE antenna arrays using patch antenna elements is proposed as a way to improve radiation performance. In the SMILE scheme, the newly proposed array feed network affects mutual coupling. It is demonstrated that proper design of the feed network may reduce mutual coupling significantly, yielding nearly ideal radiation characteristics. Results show a reduction in side lobe level of several decibels, increased accuracy in beam pointing during scan, and improved null depth and placement.; Finally, transmitter issues are addressed through the realization that variable time delay is required for the best level of error cancelation in a high power feed forward amplifier. A new circuit topology is realized in order to synthesize group delay continuously. The circuit is based upon a new variable coupling coefficient coupled line section and a microstrip feedback loop. The new variable coupler is designed by periodically loading an edge coupled microstrip coupler. With this new design, coupling variation of more than 10 dB may be achieved. To the best of the authors knowledge, this is the first report of this type of microstrip coupler. The complete circuit consumes no DC power and exhibits more than 500 ps of continuous variable true time delay.
机译：本文介绍了微波自适应前端中使用的几种新架构。无线通信系统中对自适应系统硬件的需求正由多种因素驱动，例如性能和预算。为了同时提高性能和系统成本，可以自适应地控制无线系统中的接收器和发送器。研究的第一类系统是具有自适应波束成形的新型智能天线阵列接收器。通过使用新的本地元素空间复用（SMILE）方案，该新颖的系统大大降低了智能天线系统的硬件要求。在该方案中，阵列的单个元件顺序地连接到信号处理电路，以便对输入的调制载波进行采样。选择采样率，以便可以在后期阶段完全恢复原始信号的信息。此系统为 N 元素数组提供了硬件的 N 减少。讨论了系统原理，SNR，优势和硬件，包括新型的阵列馈送网络。通过对数字调制数据进行的链接测试来验证系统性能。天线阵列的射频辐射性能值得关注，因此进行了研究。提出了一种使用贴片天线元件减少SMILE天线阵列中相互耦合的新方法，作为提高辐射性能的一种方法。在SMILE方案中，新提出的阵列馈送网络会影响相互耦合。结果表明，馈电网络的正确设计可以显着降低互耦，从而产生近乎理想的辐射特性。结果显示旁瓣水平降低了几个分贝，扫描过程中光束指向的准确性提高，并且空位深度和放置位置得到了改善。最后，通过认识到在高功率前馈放大器中为了达到最佳的误差消除水平，需要可变的时间延迟来解决发射机问题。为了连续合成群时延，实现了一种新的电路拓扑。该电路基于新的可变耦合系数耦合线段和微带反馈环路。通过定期加载边缘耦合微带耦合器来设计新的可变耦合器。利用这种新设计，可以实现超过10 dB的耦合变化。据作者所知，这是这种微带耦合器的首次报道。整个电路不消耗任何直流电，并且具有超过500 ps的连续可变真实时间延迟。

著录项

  • 作者

    Fredrick, Jonathan D.;

  • 作者单位

    University of California, Los Angeles.;

  • 授予单位 University of California, Los Angeles.;
  • 学科 Engineering Electronics and Electrical.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 84 p.
  • 总页数 84
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 无线电电子学、电信技术;
  • 关键词

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