Illusion Mechanisms with Cylindrical Metasurfaces: A General Synthesis Approach

We explore the use of cylindrical metasurfaces in providing several illusion mechanisms including scattering cancellation and creating fictitious line sources. We present the general synthesis approach that leads to such phenomena by modeling the metasurface with effective polarizability tensors and by applying boundary conditions to connect the tangential components of the desired fields to the required surface polarization current densities that generate such fields. We then use these required surface polarizations to obtain the effective polarizabilities for the synthesis of the metasurface. We demonstrate the use of this general method for the synthesis of metasurfaces that lead to scattering cancellation and illusion effects, and discuss practical scenarios by using loaded dipole antennas to realize the discretized polarization current densities. This study is the first fundamental step that may lead to interesting electromagnetic applications, like stealth technology, antenna synthesis, wireless power transfer, sensors, cylindrical absorbers, etc.Comment: 12 pages, 9 figure

Action Potential Blocking and Directional Firing by Electrical Field Induction, Modeling and Discussion

Many invasive and non-invasive methods have been proposed to excite a neuron in the nerves system. For non-invasive methods like Transcranial Magnetic Stimulation (TMS) there is few investigation on the shape and property of the induced electrical field and its interaction with a neuron to directionally fire or block an action potential. In this article, E-fields are generated by two capacitive plates as a source. E-fields are modified in MATLAB and induced on a pyramidal neuron to study the effect of E-field on a neuron. A method is proposed to block action potential (AP) or fire and direct it into the desired direction by a non-invasive method. Blocking AP can be useful for pain reduction or anesthesia in a desired region of the body. A full modeling investigation on required form of E-field, Hyper-polarization and depolarization values in membrane potential and induction time to directionally fire or block AP have been discussed for various dendrite diameters and channel densities in one-dimensional and two-dimensional pyramidal neurons