Abstract: An active magnetic antenna with a ferrite core having a winding is provided, forming a frame magnetic antenna which is connected with a low-noise transistor, to amplify a signal of the frame magnetic antenna. A base of the transistor is connected directly to one contact of the winding, and a second contact of the winding is capable of shifting a voltage of the base of the transistor. The impedance of the frame magnetic antenna is adjusted as a complex conjugate with an impedance of the base of the transistor of the low-noise amplifier, and the winding eliminates its own resonances.

Abstract: An active magnetic antenna with a ferrite core having a winding is provided, forming a frame magnetic antenna which is connected with a low-noise transistor, to amplify a signal of the frame magnetic antenna. A base of the transistor is connected directly to one contact of the winding, and a second contact of the winding is capable of shifting a voltage of the base of the transistor. The impedance of the frame magnetic antenna is adjusted as a complex conjugate with an impedance of the base of the transistor of the low-noise amplifier, and the winding eliminates its own resonances.

Abstract: A dual band antenna for a radio terminal consists of a retractable whip antenna and a helical antenna with irregular pitches, wherein the whip antenna is independent of the helical antenna. The helical antenna includes first and second helical portions having first and second pitches, respectively and the first and second helical portions are operable at different frequency bands independently. The whip antenna includes a conductive core line, a conductive substance covering a first portion of the conductive core line to serve as a choke and an isolation element extending from an upper end of the conductive core line, for filling a gap between the conductive core line and the conductive substance. Here, only the first portion of the conductive core line is operable at a first frequency band and the entire conductive core line is operable at a second frequency. A fixing element fixes the helical antenna and the whip antenna to the radio terminal.

Abstract: An antenna apparatus for a mobile terminal is provided having a hula hoop antenna secured to a housing of the mobile terminal; a conductive line coupling the hula hoop antenna to a transceiver of the mobile terminal; a conductive fixing member having a through hole and contacting a portion of the hula hoop antenna; a cylindrical fixing member inserted into the through hole of the conductive fixing member; and a rod antenna extendable and retractable from and into the housing. The rod antenna is movable along a central axis of the cylindrical fixing member. The hula hoop antenna has a first end connected to a variable capacitor on a printed circuit board of the mobile terminal and a second end connected to a ground plate of the printed circuit board.

Abstract: A dual band antenna with a simple and compact structure includes an inductor, first and second rod-like radiating elements connected to opposite ends of the inductor, with dielectric material surrounding both the inductor and the joining portions of the first and second radiating elements on the respective ends of the inductor. A conductive housing surrounds the dielectric and supports the inductor and the joining portions of the first and second radiating elements. The housing and dielectric create a capacitance, so that an LC resonant circuit is formed in conjunction with the inductor. The LC circuit is designed such that only one radiating element radiates at the higher band of the dual operating band, whereas both radiating elements radiate at the lower band.

Abstract: A dual band antenna for mobile communications includes a rod-shaped radiating element having a first portion of a predetermined length connected to a coaxial feed line, and a second portion of a specified length integrally extended from the first portion. The coaxial feed line connects to a ground plate, and a first capacitive load connects to the first portion of the radiating element. A choke surrounds the second portion of the radiating element, and has a shorting end connected to a distal end of the second portion and an open end at a proximal end of the second portion. A second capacitive load connects to the shorting end of the choke. In a higher operating band of the dual band, the input impedance of the choke is high, such that only the first (lower) portion of the radiating element radiates. At a lower operating band of the dual band, the choke's input impedance is lower to allow for radiation from the entire length of the antenna.