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:
Apr. 23, 1991
Filed:
Feb. 08, 1990
Kenneth C Kelly, Sherman Oaks, CA (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
An array antenna (20) that avoids the generation of grating lobes or second order beams is formed of a two-dimensional array of radiating elements (40) disposed in parallel rows (22) and parallel columns (24), each of the radiating elements being formed as slotted apertures within a top broad wall (28) of a waveguide (26). The width of the broad wall is many times greater than the height of a sidewall (32, 34) of the waveguide, the waveguide having a rectangular cross section. A wave launcher (46) connected to a first end of the waveguide launches a higher-order mode of electromagnetic wave wherein the order of the mode is equal to the number of columns of the radiating elements. A set of vanes (48, 48A) upstanding from a bottom wall (30) of the waveguide extend partway towards the top wall to provide values of inductance and capacitance which resonate at the resonant frequency to inhibit reflection of the electromagnetic wave from individual ones of the vanes. Each vane extends in a plane perpendicular to the sidewalls, individual planes of the vanes bisecting slots (40) of the radiating elements, the slots being arranged parallel to the sidewalls. In each column, the locations of vanes are staggered from side to side so as to offset a path of propagation of the wave in the vicinity of the radiating element to reverse a sense of coupling of electromagnetic power from the wave to the radiating element. This produces a uniform phase front from radiations from all of the radiating elements.