Accession Number : ADA259500


Title :   Performance of the Monopole Antenna Element for the 96-Element Receiving Array of the High-Frequency, High-Resolution Experimental Site: Volume 1 - Theory and Numerical Results


Corporate Author : MITRE CORP BEDFORD MA


Personal Author(s) : Lagace, R L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a259500.pdf


Report Date : Dec 1991


Pagination or Media Count : 129


Abstract : The theoretical performance of the antenna element for the 96-element receiving array of MITRE's High-Frequency, High-Resolution Experimental Site is analyzed. The antenna element consists of a monopole tower with a buried radial- wire ground screen of modest diameter. Each element is connected by a long buried coaxial cable to an associated receiver in one of three electronics shelters within the array. The analysis forms the basis for selecting the final design configuration of the monopole antenna element, its associated ground screen, and the buried feed cable. System internal noise figure and antenna directivity serve as the principal measures of performance. The contributions of antenna efficiency, cable mismatch loss, cable attenuation loss, and receiver noise figure to system internal noise figure are treated. The monopole antenna element and an alternative dipole antenna element are modeled and analyzed using the Numerical Electromagnetics Code-Ground Screen (NEC-GS) version of the NEC method-of-Moments software. NEC-GS, which is particularly well-suited for modeling azimuthally symmetric structures, is used to calculate the antenna input impedance, efficiency, and power gain pattern. The antenna efficiency, cable mismatch loss, and antenna directivity pattern are determined as a function of frequency, earth electrical properties, and antenna element/ground- screen geometry. Asymmetric radiation pattern effects caused by a long, buried or unburied, coaxial feed cable, and by a nearby electronics shelter, are also evaluated. This is accomplished by using NEC software versions NEC-3I and N-EC-3 to model the monopole with ground screen in the presence of a jacketed feed cable and a shelter, respectively.


Descriptors :   *ELECTRICAL PROPERTIES , *RECEIVERS , *MONOPOLE ANTENNAS , *COAXIAL CABLES , *DIPOLE ANTENNAS , FREQUENCY , INPUT , ELECTRONICS , DIAMETERS , HIGH FREQUENCY , MODELS , GAIN , IMPEDANCE , METHOD OF MOMENTS , NOISE , POWER , ATTENUATION , GEOMETRY , PATTERNS , DIPOLES , ANTENNAS , POWER GAIN , RADIATION PATTERNS , ELECTROMAGNETISM , ANTENNA ARRAYS , CONFIGURATIONS , SOILS , WIRE , CABLES , ARRAYS , EFFICIENCY , HIGH RESOLUTION


Subject Categories : Soil Mechanics
      Electrical and Electronic Equipment
      Electricity and Magnetism


Distribution Statement : APPROVED FOR PUBLIC RELEASE