On One- and Two-Dimensional Electromagnetic Band Gap Structures in Rectangular Waveguides at Microwave Frequencies

Abstract

Electromagnetic band gap (EBG) structures of two different configurations implemented inside R120 rectangular waveguides (frequency range 10-15 GHz) are examined. The first configuration has a periodic, piecewise uniform variation of permittivity in the propagation direction. Two types of such one-dimensional (1D) EBG structures are analyzed, one with the unit cell comprising two dielectric layers, the other with three dielectric layers per unit cell. The second configuration is two-dimensional, with the unit cell along the propagation direction containing two sections, each of which is made of alternating pillars of two dielectric materials. The Bloch theorem is invoked for the ideal EBG structures, which are infinitely long in the propagation direction. The mode-matching method (MMM) is used for real 1D-EBG structures, which contain a finite number of unit cells, whereas a combination of the coupledmode method (CMM) and the MMM is used for real 2D-EBG structures. Spectrums of the transmission coefficient of the fundamental mode for the 1D-EBG structures are computed and shown to compare favorably against experimental data. The effect of inserting a defect in 1D-EBG structures is demonstrated theoretically as well as experimentally. The band gaps computed for real and ideal 2D-EBG structures are compared as well.

Photonic Crystal Waveguides

“…The results of theoretical analysis on the characteristics of one-dimensional microwave photonic crystals made on the basis of a rectangular waveguide and their experimental investigation are given, for example, in [14]. The one dimensionality of the crystal means that the dielectric structure that fills the waveguide has a periodicity of dielectric permittivity in one direction (along the wave propagation direction, along the Z axis).…”

“…The one dimensionality of the crystal means that the dielectric structure that fills the waveguide has a periodicity of dielectric permittivity in one direction (along the wave propagation direction, along the Z axis). The authors of [14] studied structures in the form of alternating layers with high dielectric permittivity h and low l (hlpairs) and layers of the h 1 lh 2 type (h 1 and h 2 are dielectrics with different permittivities). In the theoretical description, the scattering matrix method was used.…”

“…The authors of [14] proposed to obtain reflection and transmission coefficients using the generalized scattering matrix, which is a result of the application of continuity conditions on media boundaries. The results of measurements and calculation of the transmission coefficient (S 21 ), characterized by the presence of a forbidden band for microwave photonic crystals consisting of 10 and 20 separate two-layer elements, are presented in [14]. The authors of [14] refer some of the differences between experiment and theory [14] to the imperfection of the waveguide walls.…”

Характеристики Дефектной Моды Одномерного СВЧ Волноводного Фотонного Кристалла С Металлическим Включением В Элементе, Нарушающем Его Периодичность

“…Новые возможности при создании СВЧ устройств открываются при использовании периодических струк-тур, получивших название фотонных кристаллов [1][2][3]. Эти структуры состоят из периодически расположенных элементов, размеры которых сравнимы с длиной волны распространяющегося в них электромагнитного излу-чения.…”

Mutual Conversion of Tm_mn and Te_mn Waves by Periodic and Aperiodic Waveguide Filters Composed of Dense Metal-Strip Gratings

“…The most known structures with simple periods are the sequences of dielectric layers which found wide applications as optical and microwave devices [1][2][3][4][5]. They are parts of distributed Bragg reflectors, antireflection coatings, interferometers, lasers, antennas, filters, absorber materials and many others.…”