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:
Oct. 05, 1993
Filed:
Mar. 11, 1991
Arthur C Lind, Chesterfield, MO (US);
Frederick C Wear, St. Louis, MO (US);
McDonnell Douglas Corporation, St. Louis, MO (US);
Abstract
There is provided by this invention an open-ended cavity microwave applicator apparatus for inducing current into an electrically conductive workpiece to be heated without need for the the applicator to be in contact with the workpiece. The microwave applicator is comprised of an open-ended housing that defines a cylindrical cavity which is coupled by an aperture to a waveguide which transmits the microwave energy from a microwave generator to the cylindrical applicator cavity. The microwave applicator is designed to operate in a subset of the circular TE.sub.mnp modes where m, n and p are the number of half wavelength variations in the standing wave pattern in the .theta., r,and z directions, respectively. The particular subset desired is the one in which m is equal to zero such that no current flows from the applicator to the electrically conductive workpiece. Of the subset of axially symmetric modes, TE.sub.0np, the preferred mode of operation is circular TE.sub.011. A conductive back plate forms one end of the applicator cavity while the other end is open so as to allow the microwave radiation to induce closed-loop currents in the workpiece being heated. The conductive back plate may be adjustable so as to vary the axial cavity length to accomodate variations in generator operating frequency and in the distance between the applicator and the workpiece. Furthermore, the applicator cavity may be filled or partially filled with one or more dielectric materials, either isotropic or anisotropic, to alter the physical size and shape of the cavity while supporting the same frequency of TE.sub.mnp circular mode microwave radiation.