Experimental and numerical analysis of a carousel stirrer for reverberation chambers
The paper analyzes the performance of a reverberation chamber equipped by a “carousel” stirring system. The working volume is positioned inside the stirrer rotating volume. More precisely, the carousel consists of several vertical strips that rotate around a central axis and having a total diameter as large as possible compared to chamber dimensions. An FDTD code, optimized for reverberation chamber simulations and tested with experimental results, is used to analyze the chamber performance as function of strip number and width. The proposed setup increases the working volume and improves the reverberation chamber behavior with respect to a traditional setup. Moreover, it needs just one motor to control the stirrer, and it does not require more complex mechanical part. All simulations are compared to measurements showing a good agreement.
Analysis of the Independent Positions of Reverberation Chamber Stirrers as a Function of Their Operating Conditions
The independent positions of the stirrers are computed when one or two stirrers rotate inside the chamber. In the case of the two operating stirrers, they are moved in both tuned and stirring modes. In the tuned mode, they are rotated in a synchronized or interleaved way, showing that this second modality yields a larger independent position number. In the stirring mode, both modalities are replicated varying the rotation speed. In the case of one stirrer and two synchronized stirrers, the independent positions are computed using the classical autocorrelation function, whereas in the case of two completely independent stirrers a 2-D autocorrelation is proposed. The result obtained in this second way does not depend on the order chosen to move the stirrers. The performance of the stirrers is also verified checking the ratio between the maximum and the average received power inside the chamber, the statistics of the received power by applying a goodness-of-fit test, and the uniformity of the field in some points of the working volume. Tuned and stirring operating modalities are also compared in terms of measurement time, calibration and software complexity, motor stress, and so on.
Coexistence Between Ultra-Wideband Radio and Narrow-Band Wireless LAN Communication Systems—Part I: Modeling and Measurement of UWB Radio Signals in Frequency and Time
The correct modeling and measurement of ultra-wideband (UWB) radio signal are a critical issue to evaluate the electromagnetic (EM) emission of any communication system based on this technology. In this paper (Part I), UWB radio communication systems based on impulse radio (IR) and multiband orthogonal frequency division multiplex (MB-OFDM) technologies are characterized by simulations and experiments in both frequency and time domains. The EM characteristics of UWB radio are measured by different methods (conducted and radiative) and in different environments (anechoic and reverberation chambers).