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arXiv · 1906.03331

Experimental Demonstration of Sixth Order Degenerate Band Edge in Coupled Microstrip Waveguides

Farshad Yazdi·Dmitry Oshmarin·Tarek Mealy·Ahmad T. Almutawa·Alireza Nikzamir·Filippo Capolino
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Abstract

We show the physical realization and experimental demonstration of an exceptional point of 6th order degeneracy in a triple ladder (or three-way) microwave waveguide realized using three coupled microstrips on a grounded dielectric substrate. This threeway waveguide supports six Bloch eigenmodes and all coalesce onto a degenerate single eigenmode at a given frequency. The three-way waveguide is gainless, and this exceptional point is associated to a vanishing group velocity and its multiple derivatives. Indeed the wavenumber-frequency dispersion diagram, that we call 6th order degenerate band edge (6DBE) has six coalescing branches. We provide the experimental verification of a 6th order exceptional point by evaluating the degenerate wavenumber-frequency dispersion diagram from the measurement of scattering parameters of a six-port unit cell. We also show the resonant behavior of a cavity made of the three-way waveguide with finite length. The unique properties of 6DBE can be exploited in designing innovative high-Q resonators, oscillators, filters, and pulse shaping devices.

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Farshad Yazdi, Dmitry Oshmarin, Tarek Mealy, Ahmad T. Almutawa, Alireza Nikzamir, Filippo Capolino. 2019-06-07. Experimental Demonstration of Sixth Order Degenerate Band Edge in Coupled Microstrip Waveguides. https://arxiv.org/abs/1906.03331

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