Negative Group Delay Theory on Li Topology

Computational Topology Group Theory Afra

Last lecture, we learned about a combinatorial method for characterizing spaces: using simplicial complexes as triangulations of the spaces. We also showed how the connectivity of compact 2-manifolds is fully characterized by an invariant, the Euler characteristic, that may be computed using any triangulation of the space. In this lecture, we study group theory. This theory is part of the beaut...

Negative group velocity and group delay in left-handed media.

The dynamics of wave propagation in media with negative index of refraction is analyzed through analytical calculations, simulations, and experiments. Using a free space setup, the transmission characteristics of two split ring resonator and strip wire left-handed media (LHM), designed for operation at K -band frequencies (18-26 GHz), are measured. The first LHM, which is 3 unit cells long in t...

Nilpotency in Group Theory and Topology

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Low Correlation Mimo Antennas with Negative Group Delay

Abstract—A key feature of upcoming 4G wireless communication systems is multiple-input-multiple-output (MIMO) technology. To make the best use of MIMO, the antenna correlation between adjacent antennas should be low (< 0.5). In this context, we propose a correlation reduction technique suitable for closely spaced antennas (distance, d < λ/40). This technique reduces mutual coupling between ante...

Broadband Microwave Negative Group Delay Transmission Line Phase Shifters