MINIMUM-SCATTERING ANTENNAS
Abstract
Antennas with identical patterns differ to the extent in which they modify an incident wave, i.e., in the amount they scatter. An antenna is completely described by an (infinite dimensional) scattering matrix. The concept of a minimum scattering antenna introduced by Dicke is generalized to include antennas with a finite number of accessible waveguide ports and with non-reciprocal components. A canonical minimum scattering antenna is defined as one which becomes 'invisible' when the accessible waveguide terminals are open circuited. Such an antenna is shown to be unique once the independent radiation patterns have been specified. Neither an impedance nor an admittance matrix for such an antenna exists. The physical significance of the minimum scattering antenna concept is examined from several points of view. Appropriate generalizations of Dicke's results are derived for multiport and non-reciprocal antennas. The 'scattered power', is introduced as a convenient measure of scattering. It is demonstrated, for a large class of antennas, that the scattered power is quite generally greater than the absorbed power, equality being attained for minimum scattering antennas of this class. This result further justifies the minimum-scattering terminology. Arrays of canonical antennas are discussed briefly.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 07, 1964
- Accession Number
- AD0624080
Entities
People
- Herbert Kurss
- Walter K. Kahn
Organizations
- New York University Tandon School of Engineering