Said M. Mikki

Radiation energy of antenna fields: Critique and a solution through recoverable energy

The present paper aims at introducing a general critique of some existing approaches to electromagnetic energy, followed by a theory of stored energy explaining a recent experiments proposed by the authors to define stored energy as recoverable energy.

Design of CNT-based perfect absorbers over SWIR to LWIR frequencies for sensing applications

Carbon nanotubes (CNT) are known for their use in solar thermal technologies due to their high absorption across the solar band. We design structural arrays of circular shaped CNT disc on conducting metallic film (Ag) that give rise to specified absorption bands at short-wavelength infrared (SWIR) to long-wavelength infrared (LWIR) frequencies. We note that nearly 99 % of absorbance occurs at the wavelength of 11.8 μm in the absorbance spectrum. In addition to that, other two peaks are at the wavelength of 5.6 μm and 7.8 μm with nearly 70 % and 80 % of absorbance respectively. The high absorbance at the wavelength of 11.8 μm is primarily due to the dipolar resonance while other peak positions in the spectrum are due to the higher mode and the vertical cavity mode resonances. Further, it is been shown that the simple design of CNT based perfect absorber can be used as sensing application at the infrared frequencies.

A phenomenological electromagnetic theory of CNT-DNA metabiomaterials for applications to biosensing and DNA sequencing

We model DNA-wrapped carbon nanotubes (CNTs) as loaded conducting thin-wire antennas and use MoM to solve for currents induced in hybridized CNT-DNA samples. The coupling between CNT and DNA is phenomenologically treated as a “DNA impedance perturbation” and is inserted into the CNT MoM formulation. The model is valid for arbitrary shaped CNT-DNA geometries and is expected to be accurate for low, RF, and optical frequencies. We utilize the EM model to propose a machine learning framework that can be deployed for electromagnetic DNA sequencing and biosensing.

Bandwidth-enhancement of digital communication systems employing narrowband antennas: A novel electromagnetic OFDM approach

A new approach to antenna system design is proposed achieving significant bandwidth enhancement without modifying the antennas physical layout. By deploying a complete electromagnetic link impulse response incorporating full Tx/Rx antenna effects, a novel electromagnetic OFDM (EM OFDM) scheme is developed to implement wideband digital communication systems employing narrowband antennas. An example of two wire-antenna BPSK system demonstrated about %100-bandwidth increase with probability of error performance significantly better than the typical (no EM OFDM) case.

A novel massively-parallel processing framework for real-time MIMO and smart antenna array beam control

We propose a new algorithm for real-time implementation of antenna array synthesis and processing using a novel gradient population optimization algorithm implemented on a heterogeneous computing platform which involves dataflow graphs and graphics processing units.

A new algorithm for radar target identification using a GPU-accelerated ACGF-SEM technique

We develop a new inverse scattering algorithm suitable for radar applications, especially target identification. The algorithm is a machine learning technique where the echo received from a target or antenna is analyzed into a set of characteristic singularities that can reveal important information about the target. The algorithm is suitable for implementation on scalable GPU platforms.

A New Technique for the Analysis of Energy Coupling and Exchange in General Antenna Systems

This paper provides a deeper insight into the nature of electromagnetic interactions by studying practical settings of strong and weak mutual coupling involving typical antenna elements coupled through the near field. We develop new techniques capable of analyzing the dynamic structure of generic antenna-antenna interactions by describing how energy exchange is divided between propagating and nonpropagating parts in a way reflecting the geometrical shapes and interelement distances of the coupled antennas. The proposed method is implemented through a special method-of-moment (MoM) numerical model and is used to give information about how energy is localized between antennas or electromagnetic objects, which is directly related to the physics of complex systems and the problem of energy storage, transfer, and manipulations. The work utilizes some recent developments in which a spectral near-field theory and the antenna current Greens function formalism were proposed to analyze and describe general electromagnetic systems. The present formulation is developed in conjunction with the special MoM implementation to generate various numerical illustrations and new field energy density pictures combined with analysis of the physics of near-field coupling as revealed through the new results. The technique realized here can be easily integrated into existing full-wave solvers such as MoM to provide systematic pictures of near-field interactions and coupling with more comprehensive and detailed information compared with conventional port parameters such as the S-matrix. The method is suitable for applications such as near-field detection, energy transfer, and near-field communications, besides its fundamental importance for mutual coupling in antenna arrays in general.