Abstract: A volumetrically compact and efficient antenna, with a high radiation resistance and low losses, that can be designed for any frequency, and which has a gain within 1 dB of that of a full-sized vertical monopole radiator or, in its horizontally polarized form, within 2 dB of that of a horizontally polarized half-wave dipole. One embodiment is a rectangle, with short radiators and long interconnecting wires, which has been folded back on itself in a manner that results in a square configuration (when viewed from the top) and brings the two radiating wires into close proximity. Only a single port need be fed. Linear loading sections, such as stubs, serrations and helically wound interconnecting wires can be used to electrically lengthen the antenna, while keeping physical dimensions small. Capacitive loading sections are also used. Two unequal-sized rectangular loops may be joined onto each other, to provide an additional radiating element.

Abstract: An antenna comprises a first electrically conductive loop; a feed point for feeding radio frequency energy into the first conductive loop; and a second electrically conductive loop, the first electrically conductive loop and the second electrically conductive loop each having a common conductive portion. A tuning capacitor is disposed along the second conductive loop The second conductive loop is disposed within the first conductive loop. The first conductive loop may be polygonal or circular. The first and second conductive loops may be rectangular. The second conductive loop may be a conductor connected between a first point on the first conductive loop and a second point on the first conductive loop. A method for configuring this class of antennas includes the step of placing a capacitor in the second conductive loop.

Abstract: A series of antennas with a three-dimensional structure based on the folding back onto themselves of planar multi-loop arrays of more than two elements is provided. In this way, more compact antennas are provided, with improved broadband design capabilities and wider bandwidths, both in impedance and gain. A three-dimensional antenna array comprises a plurality of rectangular full-wave loops arranged in a three-dimensional array, comprising a plurality of radiators, each radiator having two ends, and a plurality of transmission lines, each transmission line connecting a pair of the radiators through a corresponding end of each connected radiator, wherein each of the plurality of radiators is fed from a common feedpoint substantially at a geometric center of the three-dimensional antenna array.