The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 28, 1998
Filed:
Aug. 08, 1997
Shuji Maeda, Osaka, JP;
Tsutomu Kobayashi, Kyoto, JP;
Munehiko Itoh, Osaka, JP;
Raj Mittra, Urbana, IL (US);
Ikmo Park, Kwanchun, KR;
Supriyo Dey, Champaign, IL (US);
Matsushita Electric Works, Ltd., Osaka, JP;
Abstract
A compact antenna for circular polarization comprises a substrate of a dielectric material which is formed on its bottom surface with a ground plane and on its top surface with four planar rectangular patches of an electrically conductive material. The four patches are mounted in a coplanar relation on the top surface of the substrate, and arranged along four sides of a square pattern with the length of each patch angled at 90.degree. with respect to the length of the two adjacent patches. Each of the four patches is short-circuited to the ground plane at a shorting point located at a corner of the square pattern. A 90.degree. hybrid circuit is connected to directly feed only the two adjacent patches with a phase difference of 90.degree. to thereby define these two patches as active antenna elements which are fed with 0.degree. and 90.degree. signals, respectively. The other two adjacent patches are not fed from the hybrid circuit to define parasitic antenna elements each coupled with the adjacent active antenna element to provide a signal which is 90.degree. out of phase with a signal on the adjacent active antenna element. Thus, the active and parasitic antenna elements arranged in one direction around the substrate are fed at 0.degree., 90.degree., 180.degree., and 270.degree. phases for circular polarization only with the use of a single hybrid circuit.