Circularly polarized phased array antenna element

Abstract

A phased array antenna element which provides good circular polarization over a broad sector of coverage in an array environment has been designed and evaluated. The concept is the superposition of complementary antennas, the dipole, and the slot, to achieve equal <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</tex> - and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</tex> -plane patterns in the array environment. This element, when evaluated in a large test array, demonstrated an ellipticity of less than <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\pm2.0</tex> dB over a coverage of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\pm60</tex> degrees. By proper control of the excitation of the two isolated antennas any desired polarization can be achieved.