Patent Nr : US20140266940A1
Title: Antenna arrangement
This invention relates to an antenna arrangement and to an antenna array comprising the arrangement, including a collapsible arrangement and array.
In radio direction finding applications, it is known to use loop-based Watson-Watt arrays or Adcock arrays. Loop-based Watson-Watt arrays are generally perceived to be inferior to Adcock arrays, mainly due to the inherent sensitivity of loop-based radiators to horizontal polarization (HP), which causes unavoidable estimation errors when the incoming wave is not purely vertically polarized (VP), and secondly, due to inaccuracy when waves are incident from high angles of elevation. These problems often come to the fore at low frequencies (in the HF band) with sky wave propagation, but not ground wave propagation. At higher frequencies, however, ground waves support appreciable HP and loops then suffer accuracy degradation due to cross-polarization making them unpopular for use in the upper HF and VHF regions and above. Adcock arrays suffer a disadvantage over loop elements from a sensitivity point of view when the arrays are small in size, which makes Adcock arrays less desirable for use in small tactical systems that are expected to work below 100 MHz. Read more about the Antenna Arrangement Patent by Alaris Antennas
Patent Nr : US8698693B2
Title: Collapsible antenna
This invention relates to antennas and more particularly to collapsible antennas.
Log periodic dipole array (LPDA) antennas are well known wideband antennas that are commonly used in communications, monitoring and electronic warfare applications. The antenna comprises a boom and a plurality of radiating elements that are arranged substantially coplanar with each other and at right angles to the boom. Currently, these antennas are transported in one of two forms—either as a fully assembled and operative antenna, or, in the form of a boom, which may comprise a plurality of sections, and a plurality of radiating elements which are supplied and transported separately and which are first attached to the boom, when the antenna is assembled. In the first form, the antenna often is too bulky and takes up too much space. In the second form, it takes up unnecessary time and requires skill to assemble the antenna. Read more about the Collapsible Antenna Patent by Alaris Antennas