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Poster Session II

4:30 pm – 6:30 pm, Wednesday October 15 Session DW5 COEX, Lobby E
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Nonreciprocal Time-Invariant Leaky Waves Enabled by Magnetized Plasma

Poster 54
Presenter: Armin Ewert (University of California, San Diego)
Author: Daniel Sievenpiper (University of California San Diego)

This work demonstrates a topological nonreciprocal time-invariant leaky-wave antenna based on magnetized plasma in the Voigt configuration. The structure consists of a magnetized plasma layer (density 1e18 m−3, plasma frequency fpe 9 GHz, collision frequency 1 GHz) interfaced with a finite thickness dielectric substrate and vacuum. The plasma is biased with a magnetic field of 80 mT (cyclotron frequency fce 2.24 GHz). TM0 surface waves are launched along the dielectric-vacuum interface, transitioning into radiative leaky-wave modes. Experimental measurements demonstrate an 8 dB gain asymmetry between transmission and reception at 5 GHz, reversible by inverting the magnetic field polarity. Two frequency bands exhibit nonreciprocal radiation: 4–6 GHz and 6.5–9 GHz. These nonreciprocal leaky modes are predicted by the derived dispersion relation. Radiation patterns are measured in three configurations: magnetized plasma, unmagnetized plasma and absence of plasma. Reciprocal transmission is only in non-magnetized states observable. The system achieves a compensated gain of 10 dB after accounting for impedance mismatch at the maximum nonreciprocity. Computational simulations align closely with experimental data, validating the tunability of operational frequency and nonreciprocal response through adjustments to plasma density and magnetic bias. This platform enables passive nonreciprocity without time modulation with applications in full-duplex communications, radar and sensing.

Funding acknowledgement

This research was supported by an Air Force Office of Scientific Research Multi-University Research Initiative (MURI) with Grant No. FA9550-21-1-0244.

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