The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The errors, due to stair-cased meshing, in the Shielding Effectiveness (SE) of cavities modelled with thin boundaries, in the Finite-Difference Time-Domain (FDTD) method, are examined. The errors in SE are found to be associated with the error in the surface area of the cavity caused by the use of a stair-cased mesh. An empirical solution is demonstrated, which improves the stair-cased model accuracy...
In reverberant electromagnetic environments such as reverberation chambers, shielding enclosures, vehicles and buildings, the electromagnetic energy density is often assumed to be uniform and the direction of arrival of electromagnetic waves (Poynting vector) and their polarisation is assumed uniformly distributed. This is the basis of the power balance method for electromagnetic coupling analysis...
We present a new face centered approach to the collocation of the fields for the application of a surface impedance boundary condition (SIBC). This approach deals with the ambiguities in the surface normal that arise at the edges on stair-cased surfaces.. The accuracy of the new scheme is compared to edge based and conformal approaches using both planar sheet and spherical shell test cases. Stair-casing...
Shielding effectiveness (SE) is an important measure of how well an enclosure reduces the electromagnetic (EM) field incident upon it. Commonly, when the shielding effectiveness of an enclosure is stated it is for the case when the enclosure is empty. Including contents such as printed circuit boards (PCBs) in the enclosure will affect the shielding effectiveness as the PCB absorbs EM energy. One...
Knowledge of the absorption cross section (ACS) of a printed circuit board (PCB) is essential when defining an enclosure's shielding effectiveness as it will determine how a PCB affects the internal electromagnetic (EM) field inside the enclosure. In this paper we show how the ACS changes when a PCB is in the vicinity of the enclosure walls by making measurements in a small reverberation chamber....
The electromagnetic environment inside an equipment enclosure at high frequencies is strongly dependent on the absorption of energy by the contents. This effect is neglected by current shielding measurement standards. Here we extended the concept of shielding measurements using surrogate “representative contents” proposed at lower frequencies into the regime were the enclosure is electrically large...
The Absorption Cross Section (ACS) of Printed Circuit Boards (PCBs) can be used to help determine how PCBs affect the internal electromagnetic (EM) field in a shielded enclosure and thus the enclosure shielding effectiveness. Stacked PCBs inside densely populated enclosures may not have the same ACS as the sum of the individual PCBs due to ‘shadowing’ effects. In this paper ACS measurement results...
This paper describes a cost-efficient Intentional EMI Detection system and gives a brief overview of the identification and location system being developed as part of the STRUCTURES project.
This paper describes the effect of high temperature ageing on the electromagnetic emissions of a number of PIC microcontrollers. The aged devices show a measureable shift in the frequency of emissions. Shift in the voltage-current characteristics of the device output pins has also been observed.
Understanding drivers of aboveground net primary production (ANPP) has long been a goal of ecology. Decades of investigation have shown total annual precipitation to be an important determinant of ANPP within and across ecosystems. Recently a few studies at individual sites have shown precipitation during specific seasons of the year can more effectively predict ANPP. Here we determined whether seasonal...
A novel design for a dual mode antenna, intended for use in reverberation chambers, is evaluated numerically using method-of-moments simulations. The transition region between a low frequency monopole mode and a high frequency exponential taper mode in the band 200 MHz to 1 GHz is investigated and the basic design of the antenna is shown to be near optimal for a lower operational frequency of 200...
At microwave frequencies, an aircraft can be modelled as a multi-mode, reverberant EM environment. The presence of people on board will damp its resonances, thus lowering their Q-factors and increasing the propagation loss between two points. The relevant parameter is the mean absorption cross section of the body, which is of the order of one sixth of body surface area. For EM simulations of aircraft...
An orthogonal spline collocation semidiscretization, previously applied in the numerical solution of the cubic Schrodinger equation, is extended to the solution of Schrodinger equations which possess general power nonlinearities and nonlinear terms that contain derivatives. The accuracy of the method is examined, as well as its ability to conserve approximations to certain invariants associated with...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.