CONICET | Buscador de Institutos y Recursos Humanos

Experimental evidence of phase resonances in a dual-periodreflection structure comprising three subwavelength grooves in eachperiod is provided in the millimeter-wave regime. We have analyzed andmeasured the response of these structures and show that phase resonancesare characterized by a minimum in the reflected response, as predictedby numerical calculations. It is also shown that under oblique incidencethese structures exhibit additional phase resonances not present for normalillumination because of the potentially permitted odd field distribution. Asatisfactory agreement between the experimental and numerical reflectancecurves is obtained. These results confirm the recent theoretical predictionsof phase resonances in reflection gratings in the millimeter-wave regime,and encourage research in this subject due to the multiple potential applications,such as frequency selective surfaces, backscattering reduction andcomplex-surface-wave-based sensing. In addition, it is underlined here thatthe response becomes much more complex than the mere infinite analysiswhen one considers finite periodic structures as in the real experiment.