We show various examples of fully-planar two-way and three-way microstrip coupled waveguides that exhibit second, third, fourth and sixth order exceptional points of degeneracy (EPD). EPDs are shown in reciprocal waveguides that do not have gain or loss. The occurrence of EPDs is observed using three methods: (i) the mathematical description of modes and the similarity of the system matrix to a Jordan block; (ii) the dispersion diagram with prescribed flatness; (iii) the coalescence of eigenvectors that is observed analytically or experimentally. We have defined a coalescence parameter that is used in conjunction with experimental results to measure the separation of the coalescing eigenvectors (polarization states). The presented structures can serve various applications like leaky-wave antennas, distributed amplifiers, oscillators, delay lines, pulse generators, and sensors.
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Exceptional Points of Degeneracy in Waveguides with or without Loss and Gain
There are two kinds of exceptional points of degeneracy (EPD) in waveguides: those in the absence of loss and gain, related to slow light, and those where the waveguide has distributed gain and/or loss. Here, we discuss both kinds and highlight their differences. We show EPDs of order 2, 3, 4 and 6 in waveguides supporting two or three modes in each direction, and how the coalescence parameter is a good tool to measure the degree of degeneracy by measuring the angle between the eigenvectors (polarization states). In highlighting the differences between the two kinds of EPDs, we also show different sets of applications, which include sensors, delay lines, distributed amplifiers, antennas, and oscillators.
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- Award ID(s):
- 1711975
- NSF-PAR ID:
- 10421521
- Date Published:
- Journal Name:
- Published in: 2022 Sixteenth International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials)
- Page Range / eLocation ID:
- Siena, Italy
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/Metamaterials54993.2022.9920772
