Showing papers on "Metamaterial antenna published in 1943"

The Distribution of Current along a Symmetrical Center-Driven Antenna

Abstract: The cylindrical, center-driven antenna is analyzed as a boundary-value problem of electromagnetic theory. An integral equation in the current (originally obtained in a different way by Hallen) is derived. Its solution is outlined briefly and the general formula is given. Complete curves for the distribution of current for a wide range of lengths and ratios of length to radius are given. These include curves showing the components of current in phase with the driving potential difference and in quadrature with this, and curves giving the magnitude of the current and its phase angle referred to the driving potential difference. The conventionally assumed sinusoidal distribution of current is shown to be a fair approximation for extremely thin antennas and for thicker antennas which do not greatly exceed λ/2 in length.

Coupled Antennas and Transmission Lines

Abstract: The problem of coupled antennas is reviewed; unbalanced currents in and radiation from transmission lines are discussed briefly and resolved into transmission line and antenna problems. The use of sections of transmission line as coupling links between antennas is discussed qualitatively and illustrated in terms of a colinear array. The principles of phase reversing and of detuning stubs and sleeves are explained in terms of coupled circuits in which a section of transmission line may carry transmission-line currents, antenna currents, or both. Methods of driving transmission lines and of feeding antennas using transmission lines are discussed from the point of view of minimizing unbalanced currents on the line.