Abstract: A quadrifilar helical antenna comprising two pairs of filars having unequal lengths and phase quadrature signals propagating thereon. A disk-like impedance matching element disposed at a lower end of the antenna matches a source impedance to an antenna impedance. In certain embodiments a first crossbar connector on a substrate disposed at an upper end of the antenna electrically connects two helical filars to form a first filar pair and a second crossbar connector disposed on the substrate connects two filars to form a second filar pair.

Abstract: A wide band antenna. The antenna comprises a radiating element in a corner region of a substrate, spaced apart from a ground plane occupying a substantial portion of a remaining area of the substrate. Series and shunt impedance matching elements are connected to the radiating element to control the antenna operating parameters. The radiating element is connected to a signal feed.

Abstract: A radio frequency identification tag attached to an object and comprising an antenna and an integrated circuit for providing object information to a separate reader. The antenna further comprises a pair of meanderline transmission lines each terminated at a first end for conductive connection to the integrated circuit. A shorting bar connected between the pair of meanderline transmission lines at the first ends is operative to match an antenna impedance with an integrated circuit impedance.