Experimental Verification of Below-Cutoff Propagation in Miniaturized Circular Waveguides Using Anisotropic ENNZ Metamaterial Liners

Abstract

This paper presents experimental verification of below-cutoff transmission through miniaturized waveguides whose interior is coated with a thin anisotropic metamaterial liner possessing epsilon-negative and near-zero (ENNZ) properties. These liners are realized using a simple, printed-circuit implementation based on inductively loaded wires, and introduce an HE11 mode well below the natural cutoff frequency. The inclusion of the liner is shown to substantially improve the transmission between two embedded shielded-loop sources. A homogenization scheme is developed to characterize the liner's anisotropic effective-medium parameters, which is shown to accurately describe a set of frequency-reduced cutoffs. The fabrication of the lined waveguide is discussed, and the experimental and simulated transmission results are shown to be in agreement.

Dispersion peculiarities of hybrid modes in a circular waveguide filled by a composite gyroelectromagnetic medium

“…The theory of such artificial materials involves simultaneous presence of both gyromagnetic and gyroelectric effects [23][24][25][26][27][28][29] in order to reach a wide diversity of electromagnetic features of waveguide systems. It should be noted, in the subject field of interest, in recent years such gyroelectromagnetic composites are usually considered within the conception of metamaterials, in the framework of which they are widely discussed from the viewpoint of achieving below-cutoff and backward waves propagation in miniaturized circular waveguides [30][31][32][33][34].…”

Analogy Between Circular Core-Cladding and Impedance Waveguides and Their Membrane Functions

“…1), when the core region with the permittivity ε and the radius R is embedded in cladding medium. For generality (see also [35][36][37]), the cladding medium is assumed to be uniaxial anisotropic and described by the permittivity tensorε I with non-zero components ε rrI = ε φφI = ε I and ε zzI = δ I ε I . In what follows the subscript "I" denotes quantities related to the cladding region and {E I , Figure 1.…”

“…This differentiates our results from those presented in [34], which are mainly related to several special cases of frequency-dependent surface impedance. Besides, our study differs from [34] in that it concerns anisotropic cladding material [35][36][37].…”

Propagation of wave in a cylindrical waveguide filled with hyperbolic negative index medium

“…The cutoff frequency of any waveguide strictly depends on the transverse dimensions of the waveguide [21]. The waveguide with a finite cutoff frequency lacks in miniaturization without additional loading.…”