Patent ID: 8717242

Claim:
An antenna comprising: a first loop defining a first enclosed area and having a first phase center point defined by the geometric center point of the first enclosed area; a second loop coupled to the first loop and disposed substantially parallel to the first loop, the second loop defining a second enclosed area and a second phase center point defined by the geometric center point of the second enclosed area; and a third loop coupled to the first loop and the second loop and substantially parallel to the first loop, the third loop defining a third enclosed area and a third phase center point defined by the geometric center point of the third enclosed area; and a plurality of adjuster elements coupled to at least one of the first loop, the second loop, or the third loop to provide an adjustable loop and configured to expand or contract the enclosed area of the adjustable loop, wherein a line normal to the plane of the first loop passes through the first phase center point of the first loop, the second phase center point of the second loop, and the third phase center point of the third loop, and a current supplied to the antenna flows in a first polarity in the third loop and flows in a second polarity in the first loop and the second loop, the first and second polarities being opposite to each other wherein the plurality of adjuster elements comprises: a first bevel gear assembly rotatably coupled to the adjustable loop and operable to expand or contract a length of a first side of the adjustable loop; a second bevel gear assembly rotatably coupled to the adjustable loop and operable to expand or contract a length of a second side of the adjustable loop, first and second sides being opposed to each other; and a third bevel gear assembly rotatably coupled to the first bevel gear assembly and the second bevel gear assembly and operable to expand or contract the length of the first side of the adjustable loop and the length of the second side of the adjustable loop.