Summary
International Symposium on Antennas and Propagation
2010
Session Number:4FB2
Session:
Number:4FB2-2
Radiation Characteristics of a Spiral GAA and a Loop GAA
Y. Iitsuka, J. Yamauchi, H. Nakano,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
A Kraus-type grid array antenna (GAA) radiates a linearly polarized beam, whose direction varies with frequency [1][2]. The long and short side lines of each grid cell for this GAA act as the transmission-line and the radiation elements, respectively. The direction of the linear polarization coincides with the direction of the short side lines. An array antenna that radiates a circularly polarized (CP) wave is found in [3], where cfigured elements are placed above the short side lines of the Kraus-type GAA. The radiation beam from this array is in the direction normal to the grid array plane. An array antenna in [4] also radiates a CP wave, where loops having perturbation elements are used for the radiation elements. The radiation beam from this array is in the direction normal to the grid array plane, as in [3]. Note that these two grid array antennas are designed as a broadside CP array antenna and do not have a beam scanning function. Recently, the short side lines for the Kraus-type GAA have been replaced with spiral elements [5] and open loop elements (without perturbation elements) [6] in order to obtain a CP beam scanning function (the CP beam direction varies with frequency). These arrays are designated as the spiral GAA and the loop GAA, respectively. This paper presents a comparison between the radiation characteristics of the spiral GAA and the loop GAA. The axial ratio, beam direction, and radiation pattern are discussed.