Strongly Localized Singular Bloch Modes Created in Dual-Periodic Microstrip Lines

Abstract

One-dimensional dual-periodic photonic crystals were fabricated using periodic microstrip lines. Singular Bloch modes with an extremely high Q factor of 170 in the crystals were successfully obtained in the bandgap region. The measured transmission and reflection spectra were in very good accordance with those calculated by the method of moments. The spatial distribution of the electrical current in the singular Bloch modes of the electromagnetic wave was simulated using the method of moments, and the localization of the singular Bloch modes was clearly evident. The spatial distribution pattern of the electrical current in the modes was not localized in the restricted area of the line. This was not similar to that in impurity modes for a simple periodic photonic crystal, that is, the pattern expanded over the entire line.