New project: how to optimise electromagnetic fields around antennas?

Sirris is contributing to a project that consists in developing passive components (called auxiliary radiators) that can be programmed in front of telephone relay antennas to optimise the electromagnetic field.

Radiation from mobile telephone relay antennas has become an important social issue because a balance is required between technical economic development, health and environmental preservation and democratic governance.
The demand for mobile telephony and data transmission continues to grow and the advent of 4G will accelerate this trend.

However, there are worries in the population, among political decision-makers and in the medical profession, about the effects of electromagnetic waves (EMW) on health. While the social utility of mobile telephony is not in doubt, its expansion is liable to raise the NIMBY ("Not in my backyard") phenomenon as soon as a new transmitter antenna has to be installed. Public regulation is torn between the growing need to expand the network and the obligation to comply with environmental health standards. 

Many specialists think that the choice of relay station sites should be based not on the concept of maximising traffic but on the principle of minimising human exposure to electromagnetic waves, to an unchanged technical comfort level for users. 

Uniformly reducing the power of relay stations is not a satisfactory solution from the operators' point of view, even if this is employed currently. Up to now a technical solution related to the radiation diagram of relay antennas has not been exploited. 

Currently, these antennas radiate uniformly. According to UCL-ICTEAM scientists, by making radiation non-uniform on the basis of an accurate prediction of the level of the electromagnetic field, it should be possible to reduce the field in certain 'sensitive' directions (schools, populated streets, etc.) by reinforcing it in directions where it is too weak. The realisation of these new diagrams should be based on new methods of antenna design and calculation of the radio coverage.

This is the goal of the B-WARE (WB Health) project, which started in June 2014. The main result will consist in a carrier structure integrating auxiliary radiators that can be programmed on the basis of the results supplied by a propagation-optimisation program, and in the demonstration of conformity with performance and radiation specifications. The technological study will be completed with an evaluation of the social acceptability and regulatory conformity of relay antennas equipped in this way and the equipment operators and suppliers will have to analyse their legal responsibilities.

In this project, Sirris is particularly entrusted with the design and dimensioning of the support of the radiators, the choice of materials, the study of the connection problems and the production of demonstrators. 

In particular this means producing passive conductor elements (aluminium or copper dipoles) on a structurally dimensioned support. But the concept of passive dipoles is based on the controlled management of their length by using electronic switches placed in the middle of the component. This assumes the presence of continuous conductor connectors that interfere with the switch effect. Thus once the switches are adjusted, the conductor character of these elements has to disappear from the panel's passive signature. 

Sirris has now devised a concept of temporary connecting that would only be active when the installer is adjusting the radiation of the auxiliary elements. Several options are being studied, based on the techniques of printing conductor inks onto flexible substrates using equipment such as AJP (Aerosol Jet Printing). 

Partners of the B-WARE project: UCL-ICTEAM (promoter), ULB-OPERA, UNamur-CRIDS