Characteristics of the Fields in the Near and Far Zone Of Antennas and Its Significance in Wireless Communication

The characterization of the fields radiated from antennas in wireless communication scenario has been mostly overlooked by communication society. The definition and application of Near-Field and Far-field has mostly been considered from the antenna measurement community. To date no critical study does exist for the evaluation of the far-field criterion in a wireless communication scenario. This dissertation tries to provide certain guidelines characterizing the near-field and the far-field using a Maxwellian framework. The implications of the near-field environment are then discussed. It appears that the concept of near and far fields are not clearly interpreted in the wireless communication literature. This dissertation tries to provide some insight into the trade-off of the phenomenon of height-gain and the near field zone of the antenna which determines the optimum positioning of the transmitting antenna within a cellular range

Selection of Dominant Characteristic Modes

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The theory of characteristic modes is a popular physics based deterministic approach which has found several recent applications in the fields of radiator design, electromagnetic interference modelling and radiated emission analysis. The modal theory is based on the approximation of the total induced current in an electromagnetic structure in terms of a weighted sum of multiple characteristic current modes. The resultant outgoing field is also a weighted summation of the characteristic field patterns. Henceforth, a proper modal measure is an essential requirement to identify the modes which play a dominant role for a frequency of interest. The existing literature of significance measures restricts itself for ideal lossless structures only. This paper explores the pros and cons of the existing measures and correspondingly suggests suitable alternatives for both radiating and scattering applications. An example is presented in order to illustrate the proposed modal method for approximating the shielding response of a slotted geometry

Quad: countering Chinese dominance by building new supply chains

India, Japan, Australia, and the US have decided to revive the Quadrilateral Security Dialogue alliance (Quad), with a new focus on building resilient supply chains. The Quad is now focusing on creating a new COVID-19 vaccine value chain, but it aims to expand into renewable technology. Arijit De, Vishal Rana, and Parth Patel write that if the Quad is to be successful, it needs to engage other countries to increase its reach and influence