Abstract: A diversity antenna for radio communications including a pair of conductive thin-film patterns used for a first antenna and another pair of conductive thin-film patterns used for a second antenna, the thin-film patterns being installed on a printed circuit board along the direction of the length of the circuit board; a first choke coil which is used to stop a leakage current from the first antenna and cause attenuation of a coupling current from the second antenna, the first choke coil being installed at a location where the leakage current distribution of the first antenna reaches the maximum in a feeder cable connected to the first antenna; and a second choke coil which is used to stop the leakage current from the second antenna, the second choke coil being installed at a location where the leakage current distribution of the second antenna reaches the maximum in a feeder cable for the second antenna.

Abstract: A telecommunication system antenna including: a non-resonating three-wire type folded element which generates an unbalanced mode current and has a matching function; a sleeve element which consists of a conductive sleeve with its one end near the non-resonating three-wire type folded element and a conductive disk in a flange shape around the circumference of the other end of the conductive sleeve, so that the sleeve element radiates electromagnetic waves based on the unbalanced mode current generated by the non-resonating three-wire type folded element; and a coaxial line with its tip end inserted into the conductive sleeve of the sleeve element from the other end of the conductive sleeve so that the coaxial line is electrically connected to the conductive sleeve and to the non-resonating three-wire type folded element.