Enhancing Exposure Efficiency and Uniformity Using a Choke Ring Antenna: Application to Bioelectromagnetic Studies at 60 GHz

• Published in: IEEE transactions on microwave theory and techniques Vol. 61; no. 5; pp. 2005 - 2014
• Main Authors: Boriskin, A. V., Zhadobov, M., Steshenko, S., Le Drean, Y., Le Coq, Laurent, Person, C., Sauleau, R.
• Format: Journal Article
• Language: English
• Published: IEEE 01.05.2013; Institute of Electrical and Electronics Engineers
• Subjects: 60 GHz; Antenna radiation patterns; Bioelectromagnetics; Biotechnology; choke ring antenna (CRA); Computer Science; dosimetry; Electromagnetic waveguides; exposure efficiency; exposure system; Feeds; Inductors; Life Sciences; Lighting; metallized foam; millimeter waves; Optimization; uniform illumination; waveguide feed; metallized foam; choke ring antenna (CRA); dosimetry; Bioelectromagnetics; exposure system; 60 GHz; exposure efficiency; millimeter waves; uniform illumination; waveguide feed
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2013.2255619

An effective solution for increasing the exposure uniformity and efficiency of biological samples in in vitro bioelectromagnetic experiments at 60 GHz is proposed by introducing a novel choke ring antenna (CRA). The CRA is optimized to provide a uniform exposure of samples, whose dimensions are equivalent to those of a standard 35-mm Petri dish, positioned close to the antenna aperture, i.e., 10-20 wavelengths. The antenna prototype is fabricated in metallized foam. The realized exposure efficiency of the sample exceeds 55% (if estimated for an exposure uniformity better than - 0.5 dB). To validate the numerical results, the field intensity profiles on the surface of a high-water-content phantom have been experimentally obtained using a high-resolution infrared camera. Compared to the standard open-ended waveguide and horn antennas, typically used for millimeter-wave dosimetry, a twofold advantage of the proposed CRA is demonstrated, namely, the improvement of the exposure efficiency by a factor of 1.5 to 2 with a simultaneous reduction of the exposure distance by a factor of 8-2, respectively, depending on the type of the reference antenna. These advantages make the proposed CRA an excellent candidate for 60-GHz short-range exposure systems for in vitro bioelectromagnetic studies.