Pure dipole radiation via exact solution of Maxwell's equations with spherical source electric current density

Abstract

Abstract Magnetic loop antennas are valuable for low frequency radar and communications applications, especially for frequencies below 1 MHz. The present paper examines a possible new type of magnetic antenna which is based on a spherical distribution of source electric current. Specifically, this analysis examines a spherically shaped azimuthal electric current density with a magnitude that is proportional to the sine of the spherical elevation angle. A theoretic analytic investigation of the resultant electromagnetic (EM) fields yields an exact closed‐form solution of Maxwell's equations which is expressed in terms of a small number of elemental functions. This emanated radiation has a purely dipole structure, with the absence of any higher order multipole contributions. This pure dipole property might offer new applications in radar and communications, provided that suitable physical antenna systems can be fabricated based on the subject theoretical concepts.

Keywords

• antenna radiation patterns
• current density
• dipole antennas
• electromagnetic fields
• electromagnetic wave propagation
• loop antennas