Accession Number : AD0427641


Title :   A Solution to the Frequency-Independent Antenna Problem


Corporate Author : CALIFORNIA UNIV BERKELEY ELECTRONICS RESEARCH LAB


Personal Author(s) : Cheo, B. R. ; Rumsey, V. H. ; Welch, W. J.


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/427641.pdf


Report Date : 08 JAN 1962


Pagination or Media Count : 15


Abstract : A solution of Maxwell's equations is obtained for an antenna consisting of an infinite number of equally spaced wires in the form of coplanar equiangular spirals. Radiation amplitude patterns obtained from this solution agree closely with measurements on two-element spiral antennas. The phase pattern shows the approximate validity of a phase center at a distance behind the antenna which decreases with the tightness of the spiral. The current distribution shows increased attenuation with increase in the tightness of the spiral, thus showing how the frequency-independent mode depends of the curvature. A remarkable feature of the solution is that the current consists of an inward traveling wave at infinity when the antenna is excited in that sense which produces an outward wave at the center.


Descriptors :   *SPIRAL ANTENNAS , MAXWELLS EQUATIONS , ANTENNA RADIATION PATTERNS.


Subject Categories : ELECTRICAL AND ELECTRONIC EQUIPMENT


Distribution Statement : APPROVED FOR PUBLIC RELEASE