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:
Dec. 26, 1995
Filed:
Apr. 19, 1995
Thomas E Koscica, Clark, NJ (US);
Richard W Babbitt, Fair Haven, NJ (US);
William C Drach, Tinton Falls, NJ (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
A ferroelectric phase shifter for shifting the phase of a radio frequency F) signal. The phase shifter includes a conductor line, a ground plane and a ferroelectric element between the conductor line and the ground plane to form a microstrip circuit through which the RF signal propagates. The ferroelectric element has a dielectric constant that can be varied as a function of a DC voltage applied to the ferroelectric element wherein the speed of the RF signal propagating through the ferroelectric element is a function of the dielectric constant. The phase shifter further includes a DC voltage source connected across the conductor line and the ground plane. The DC voltage source applies a variable DC voltage to the ferroelectric element in response to a control signal thereby to vary the dielectric constant of the ferroelectric element. The phase shifter further includes a controller circuit operating at a test frequency having a synchronous detector for detecting changes in the dielectric constant of the ferroelectric element. The controller circuit provides the control signal to the DC voltage source to vary the applied DC voltage as a function of the detected changes. In this manner, changes in the dielectric constant over time are compensated for and the phase shift is maintained substantially constant.