In brief - Your flexible friend

Ferrites are known to be effective for shielding antenna radiation, and researchers in France and India have developed a wearable antenna mounted on a polymer-ferrite sheet.

They show that this can reduce microwave absorption by the human body, and suggest that their sheet design could allow the antenna to be printed on to it for low profile, on-body applications.

Polymeric ferrite sheets for SAR reduction of wearable antennas
Electron. Lett. -- 4 February 2010 -- Volume 46, Issue 3, p.197–199

R. Augustine (1), T. Alves (1), T. Sarrebourse (2), B. Poussot (1), K.T. Mathew (3) and J.-M. Laheurte (1)
(1) Université Paris Est, Marne-La-Vallée, Laboratoire ESYCOM, Champs-sur-Marne, France
(2) Orange, France Telecom, Issy-les-Moulineaux, France
(3) Cochin University of Science and Technology, Microwave Tomography and Materials Research Laboratory, Department of Electronics, Cochin-22, India

Reduction of specific absorption rate (SAR) has now become a buzz word because of the growing health concerns over microwave exposure. Ferrites are found to be effective in diminishing electromagnetic influence. In this reported work, flexible polymeric ferrite sheets are characterised on the basis of their shielding efficiencies. SAR measurements are carried out with a planar wearable antenna and polymeric ferrite shielding to confirm its competence.

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