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.
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