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:
Mar. 17, 1998
Filed:
Nov. 27, 1996
Erik A Schuchmann, Austin, TX (US);
Stuart W Hayes, Austin, TX (US);
Joseph A Vivio, Austin, TX (US);
Dell USA, L.P., Round Rock, TX (US);
Abstract
The present application describes a tuned guard circuit device and method for controlling impedance levels of transmission lines on a printed circuit board having at least one ground plane and at least two circuit components coupled by a conductive transmission line. The guard circuit device of the present invention includes two etched conducting guard bands on the printed circuit board disposed on opposite sides of a selected transmission line and affixed in a spaced parallel relation to the transmission line. The guard bands are of substantially constant width and substantially constant distance from the ground plane and have substantially the same length as the transmission line, and each guard band has a first and a second terminal end. Also included is a capacitor connected to the ground plane and connected at each of the first and second terminal ends of each guard band wherein the guard bands are connected to ground through the capacitors. The guard circuit device controls the impedance level of the transmission line by varying the capacitance values of the capacitors to optimize the impedance level of the transmission line. The capacitance values of all the capacitors are, preferably, equal.