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:
Aug. 10, 1993
Filed:
Nov. 27, 1991
Hiroshi Saka, Katano, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In a directional coupler having four input/output terminals in a planar circuit using strip lines or microstrip lines, a quarter-wavelength line is connected between first and third terminals, and between second and fourth terminals, respectively, and furthermore between first and second terminals, and between third and fourth terminals, individually, a branch line is connected, having a length which is (2N+1)/4 wavelength, cascading (2N+1) pieces of quarter-wavelength lines (where N is a positive integer). These (2N+1) quarter-wavelength lines composing the branch lines are set so that lines of high characteristic impedance and lines of low characteristic impedance appear alternately. The (2N+1) quarter-wavelength lines in which the lines of high characteristic impedance and low characteristic impedance appear alternately function equivalently to (2N+1)/4 wavelength lines of a higher characteristic impedance, or equivalently to (2N+1)/4 wavelength lines of a lower characteristic impedance, thereby operating as a directional coupler having a small coupling coefficient or as a directional coupler of having a large coupling coefficient.