Frequency-Selective Energy Tunneling in Wire-Loaded Narrow Waveguide Channels

Abstract

Abstract-Frequency-dependent energy tunneling that results in full transmission of electromagnetic energy through wire-loaded sharp waveguide bends is demonstrated by full-wave simulations. The frequencies at which the tunneling takes place is predicted by a numerical method that involves a variational impedance formula based on Green function of a probe-excited parallel plate waveguide. Analogous tunneling effects have also been previously observed in waveguide bends filled with epsilon-near-zero media. However, since the frequency response in the wire-loaded waveguides can be tailored by simply modifying the lengths of the wires, the phenomenon is scalable over a broad range of frequencies and can be potentially exploited in various filtering and multiplexing applications.

Tunneling and Filtering of Degenerate Microwave Modes in a Polarization-Dependent Waveguide Containing Index Gradient Barriers

“…However, in our problem, one has to consider the profiles U(z), ensuring the exact analytical solutions for both Eqs. ( 10) and (11). One of these profiles is given by the so-called, Rayleigh distribution U(z) = (1 + z/L) −1 [18], containing only one free parameter: the length scale L. In terms of the variable η defined in Eq.…”

“…To visualize the effect of the gradient profile (16), the transmission coefficients for the TE 11 the same refractive index n 0 and the same thickness 2d are presented in Fig. 5 by spectra 3 and 4 respectively.…”

“…This analogy was manifested by simulation of optical left-handed media realized in split-ring-resonatorloaded waveguides [5]. The growing applications of metamaterials in the design of waveguides gave rise to the concept of waveguide metatronics [6], opening new directions in waveguide functionality, such as the use of epsilon-near-zero metamaterials for squeezing energy flows [7][8][9], frequency-selective energy tunneling in wireloaded narrow waveguide channels [10,11], and waveguide structural dispersion [12]. Structural dispersion proved to be useful for controlling the dynamics of voltage and current waves in transmission lines with continuously distributed parameters [13].…”

“…Note that the functions s (z) and p (z), related to the degenerate TE 11 and TH 11 modes in the same waveguide, are determined by two different equations ( 10) and (11).…”

Energy Tunneling Behavior in Geometrically Separated Wave Guides

“…So far, a new class of microwave components like multiplexers, filters, and dielectric sensors has been demonstrated experimentally exploiting the energy tunneling phenomena [4]- [6]. Energy tunnels through narrow sub-wave length channel filled with ENZ materials inherits high dielectric loses at low frequencies [7], and to avoid these loses they have to operate at cutoff frequency which solely depends upon the geometry of the waveguide.…”