Signal and Power Transfer Through Metal Shielding

An innovative development described recently in Interference Technology magazine (click to see article) provides a way to couple data and power through metal shielding. This has been tested by the developers through steel up to 15mm thick, and could be very useful in a multitude of monitoring-type and other applications which could benefit from the simplicity and cost saving possibly afforded by being able to pass signals and power through the walls of vessels, pipes, other enclosures and large barriers.

Of course it always has been possible to pass electromagnetic signals and possibly a little useful power through most forms of metal shielding, provided, with an appropriate system, that the often considerable power loss involved could be tolerated and/or a low frequency could be used.

Shielding does not form a perfect barrier to electromagnetic disturbances; it merely attenuates very strongly, ideally to a point of insignificance for the relevant frequencies in the context of the intended shielding purpose. And the attenuation encountered is dependent on frequency; in simple terms, increasing with higher frequency and (importantly) tending to zero at very low frequency.

The technology described apparently mitgates the attenuation encountered through steel (a very common containment material) by modifying its properties, namely by magnetically saturating an area of the wall. This reduces the effective magnetic permeability of the steel in that area, thus increasing the skin depth for any given frequency and thereby reducing the attenuation. Thus it is possible to significantly improve the practical frequency range available for coupling through a thickness of steel, and so for many walls more commonly encountered.

Patent Application Filed

Often with RF-based systems and equipment, in addition to the main RF circuit, careful attention and design is also required with regard to the support, control, protection and management circuitry and subsystems. This is especially so when high power and high speed are involved.

Thus, consequently, this aspect presents its share of design challenges, some of which can affect a large part of the whole system rather than simply be confined to some small part of it.

Solving such problems sometimes results in something novel, especially in regard of a new problem in a new area of application, creating an element of competitive advantage that should be protected.

Please see our page on Design and Development Services.

What if you suspect that you may be suffering from sporadic Electromagnetic Interference (EMI)? It could be ESD

Interference suffered by equipment does not only occur as a result of power-supply borne disturbances or from electromagnetic disturbances generated by, and conveyed from or radiated by, other electrical/electronic equipment, nor from internal problems in other parts of the equipment.

It can also arise as a result of purely mechanical phenomena, quite independent of and unrelated to any electrical or electronic system, through the creation and building up of static electric charges leading to a subsequent abrupt discharge via a spark.

Such an electrostatic discharge (ESD) does not need to be visible or audible for an electromagnetic disturbance to be produced.

While the energy of the discharge often may be small, its short duration results in high instantaneous power levels and short intense electromagnetic bursts, with potentially significant local effects.

Amongst sensitive equipments that may be affected, are some test, measurement and detection systems.

To determine the solution, it is first necessary to find the causes, and suitably-configured logging equipment will capture detailed information on large numbers of individual interference events to enable this to be done. Such equipment with an appropriately-designed Antenna and RF Amplifier can also provide information in 3 axes on the incident electromagnetic fields, to provide additional geometric and diversity data.

For more information please see our page on EMI Investigation.

Requirement for Magnet Calibration in the Food Industry

Strong permanent magnets are often used in the food industry for the detection and removal of magnetic contaminant foreign bodies.

Since January 2012, the BRC Global Standard For Food Safety has required periodic checking and recording of the strength of such magnets.

We have for some time been providing this on-site service to food manufacturers in the Manchester Area, as a natural extension of our magnetic survey service, and are pleased to have recently received another order for further repeat-business.

To learn more about our tailored service please see our new page on Magnet Calibration.

Custom RF Module Requirements Continue to be Diverse

Applications where custom-designed receiver and transmitter circuit modules are needed due to a lack of suitable off-the-shelf options continue to be quite varied, each with its own particular challenges in obtaining required operational performance despite the particular constraints in which it must operate.

Thus recently, at the same time as looking into a bespoke special-purpose audio receiver and working on a small-format safety-alert transmitter, we also developed a prototype high-stability narrowband control receiver for a non-standard frequency with stringent environmental and immunity requirements while using commercial off-the-shelf (COTS) components. It was also pleasing to realise this latter design without any adjustments or alignment being needed in production.

For more information on how we could help you with your receiver and transmitter circuit needs, please visit our web page on RF Modules.

Welcome to the new blog of WRL Consultancy.

This blog is primarily to provide items of information and insight relating to our mission of assisting and facilitating the use and development of radio-frequency, electro-magnetic and magnetic systems, technologies and products to bring about practical benefits in various fields of application.

Thus as well as updates concerning our services and activities, we will highlight and discuss selected matters of interest, including items of news.

Also from time to time there will be items of a more general nature that we find interesting and that you may too.