Accession Number : ADA306546

Title :   Active Impedance Matching for Superdirective, Super-Gain HTS Antenna Arrays.

Descriptive Note : Interim rept. Jan-Mar 95,

Corporate Author : NAVAL AIR WARFARE CENTER WEAPONS DIV CHINA LAKE CA

Personal Author(s) : White, D. J. ; Bowling, D. R. ; Overfelt, P. L.

PDF Url : ADA306546

Report Date : MAR 1996

Pagination or Media Count : 128

Abstract : The radiation pattern of a super gain antenna array is determined by specifying the antenna element currents in both magnitude and phase. The spacing between elements in such an array is small with respect to a wavelength and interelement coupling cannot be ignored. The specification of the element currents together with this coupling produces an active input impedance to each element that may be very different from the usual antenna impedance of the individual elements. For those active impedances with a positive real part, the element matching network must match this impedance. Furthermore, each matching network must be supplied with the proper input signal, in magnitude and phase, to ensure a match with the specified currents. If the active impedance has a negative real part, the matching network must be replaced with negative impedance. To avoid excess loss, this impedance can be replaced with a lossless two port, presenting this impedance to the antenna with its output signal then combined (added) to the overall input signal driving the array.

Descriptors :   *HIGH TEMPERATURE SUPERCONDUCTORS, *ANTENNA ARRAYS, *GUIDED MISSILE ANTENNAS, INPUT, NETWORKS, LOSSES, RADAR SIGNALS, ELECTRICAL IMPEDANCE, ANTENNA RADIATION PATTERNS, IMPEDANCE MATCHING, HIGH GAIN, ANTENNA COMPONENTS.

Subject Categories : Electrical and Electronic Equipment
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE