The last two decades have seen numerous investigations about the optimal design of mechanical stirrers for reverberation chambers (RCs), with the aim of improving their stirring efficiency, without leading to a clear consensus on the reasons for their limited efficiency. This article introduces a new criterion, by focusing on the incremental disorder introduced by mechanical stirrers, measured by their stirring coherence time, a measure of the rate of loss of coherence independent from the RC loading and excitation source. The model predicts that increasing losses would result in a loss of disorder and, therefore, of stirring efficiency. Therefore, the stirring efficiency is not limited by a stirrer being too small (electrically) or too simple-shaped, but by the limited time they have to introduce disorder in a lossy RC. Experimental tests confirm the accuracy of the model's predictions under variable loading conditions. The model can predict the maximum loading for which a stirrer can be acceptably efficient. It applies to electromagnetic compatibility testing of lossy devices, as well as over-the-air tests for wireless communication devices, where absorbers are introduced in order to emulate different propagation environments.

中文翻译：

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通过搅拌相干时间预测负载混响室中的搅拌器效率


在过去的二十年里，人们对混响室（RC）机械搅拌器的优化设计进行了大量研究，目的是提高其搅拌效率，但对其效率有限的原因却没有达成明确的共识。本文介绍了一种新的标准，重点关注机械搅拌器引入的增量无序，通过搅拌相干时间来测量，这是一种独立于 RC 负载和激励源的相干性损失率的测量方法。该模型预测，增加的损失将导致无序度的损失，从而导致搅拌效率的损失。因此，搅拌效率并不受搅拌器太小（电动）或形状太简单的限制，而是受到它们必须在有损RC中引入无序的有限时间的限制。实验测试证实了模型在可变负载条件下预测的准确性。该模型可以预测搅拌器可以达到可接受的效率的最大负载。它适用于有损设备的电磁兼容性测试，以及无线通信设备的无线测试，其中引入吸收器以模拟不同的传播环境。