Reverberation chambers a la carte: An overview of the different mode-stirring techniques

Reverberation chambers (RC), a name inspired in room acoustics, are also known in literature as reverberating, reverb, mode-stirred or mode-tuned chambers. In their basic form, they consist of a shielded metallic enclosure, forming a cavity resonator, together with some mode-stirring mechanism. The main goal of such stirring mechanism is to generate an amplitude-varying electromagnetic field that is ideally statistically uniform

Selection of Dominant Characteristic Modes

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The theory of characteristic modes is a popular physics based deterministic approach which has found several recent applications in the fields of radiator design, electromagnetic interference modelling and radiated emission analysis. The modal theory is based on the approximation of the total induced current in an electromagnetic structure in terms of a weighted sum of multiple characteristic current modes. The resultant outgoing field is also a weighted summation of the characteristic field patterns. Henceforth, a proper modal measure is an essential requirement to identify the modes which play a dominant role for a frequency of interest. The existing literature of significance measures restricts itself for ideal lossless structures only. This paper explores the pros and cons of the existing measures and correspondingly suggests suitable alternatives for both radiating and scattering applications. An example is presented in order to illustrate the proposed modal method for approximating the shielding response of a slotted geometry

Viking '75 spacecraft design and test summary. Volume 3: Engineering test summary

The engineering test program for the lander and the orbiter are presented. The engineering program was developed to achieve confidence that the design was adequate to survive the expected mission environments and to accomplish the mission objective

Resonance Scanning System and Method for Testing Equipment for Electromagnetic Resonances

A resonance scanning system and method for testing equipment for electromagnetic resonances uses a resonance detection subsystem with at least one probe to identify at least one of a resonating location, a resonating frequency and a quality factor of a resonance of the equipment and an automatic scanning subsystem to displace the probe to different testing locations of the equipment so that the resonance detection subsystem can determine if any of the different testing locations of the equipment exhibits electromagnetic resonances

Modeling and analysis of high-speed sources and serial links for signal integrity

As the computer and electronics industry moves towards higher data rates, signal integrity and electromagnetic interference (EMI) problems always present challenges for designers for high-speed data communication systems. To characterize the entire link path between transmitters and receivers, accurate models for sources, passive link path (such as traces, vias, connectors, etc), and terminations should be built before simulations either in frequency or time domain. Due to the imperfection of model, data corrections are preferred before time-domain simulations to ensure stability. Moreover, data obtained from models should be compared with measurement results to judge the level of agreement for validations. This thesis presents a new approach to model via structures to help design signal link path while maintaining a low insertion loss and minimizing crosstalk, borrowing the concepts from the transmission line theories. For the models of sources, a dipole model is proposed to represent integrated circuit (IC) radiation emissions while a circuit model for I/O current source is proposed for IC conductive emissions. Passivity and causality are two important properties for passive networks. This thesis also presents detailed algorithm to check passivity and causality for networks with arbitrary port numbers. Data corrections in term of passivity and causality enforcement are applied based on matrix perturbation theory. Last but not least, Feature Selective Validation (FSV) technique is expanded in this thesis to quantify the comparisons of data sets and provide quantitative standard for data optimization --Abstract, page iii

Tecniche di protezione da interferenze elettromagnetiche: modellistica e prove sperimentali in camera riverberante

Electromagnetic interference and compatibility are problems that claim an increasing attention in many environments, all over the world

Passive harmonic generation at spring contacts

In the first paper, the RF passive harmonic generation phenomenon on the spring contact is studied. A spring contact harmonic generation measurement system is developed. The factors that may have an impact on the spring contact harmonic generation, such as contact material, contact force, and contact resistance are characterized by the measurement system. The gold-to-gold contact is found to be much superior to the stainless-steel contacts. It is also found that the passive nonlinearity at the spring contact is the semiconductor-like junction formed by the surface oxide film. In the second paper, we show that the maximum E-field coupling occurs at a location slightly offset from the trace center. The E-field coupling to a shielded H-field probe at such a position leads to differential mode coupling which the standard shield of an H-field probe is unable to suppress. The coupling mechanism is investigated and a differential E-field coupling suppression approach is proposed. In the third paper, a measurement system which uses acoustic vibration to locate passive intermodulation (PIM) sources in base station antennas is presented. This measurement system uses mechanical vibration to modulate the PIM signal. By introducing the acoustic vibration at different locations in the base station antenna and observing if the PIM signal is modulated by the acoustic frequency, the most likely location of the PIM source is identified --Abstract, page iv

Aeronautical engineering: A continuing bibliography with indexes, supplement 100

This bibliography lists 295 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System in August 1978

Modeling EMI Resulting from a Signal Via Transition Through Power/Ground Layers

Signal transitioning through layers on vias are very common in multi-layer printed circuit board (PCB) design. For a signal via transitioning through the internal power and ground planes, the return current must switch from one reference plane to another reference plane. The discontinuity of the return current at the via excites the power and ground planes, and results in noise on the power bus that can lead to signal integrity, as well as EMI problems. Numerical methods, such as the finite-difference time-domain (FDTD), Moment of Methods (MoM), and partial element equivalent circuit (PEEC) method, were employed herein to study this problem. The modeled results are supported by measurements. In addition, a common EMI mitigation approach of adding a decoupling capacitor was investigated with the FDTD method