The dual-band antenna device includes: a feeding electrode that branches into a first branch feeding electrode that serves as a low-frequency signal path and a second branch feeding electrode that serves as a high-frequency signal path; and a radiation electrode having a rectangular shape with a longitudinal direction and having a low-frequency feeding point to which the first branch feeding electrode is electrically connected and a high-frequency feeding point to which the second branch feeding electrode is electrically connected. In the radiation electrode, the low-frequency feeding point or the high-frequency feeding point is formed close to an end portion of the rectangular shape in the longitudinal direction, and the high-frequency feeding point or the low-frequency feeding point is formed at a center portion of a side of the rectangular shape that extends in the longitudinal direction.

An antenna module and a mobile device are provided. The antenna module includes a radiator formed on a surface of the plastic rear housing facing the back cover, and a feed point, a first ground point, and a second ground point that are disposed on the motherboard. The antenna module further includes a matching network, a first tuning switch, and a second tuning switch. The feed point is connected to the radiator through the matching network. The first ground point is connected to the radiator through the first tuning switch. The second ground point is connected to the radiator through the second tuning switch. The surface of the plastic rear housing facing the back cover includes a first shaping zone for shaping the radiator and a second zone other than the first shaping zone, and the radiator completely covers the first shaping zone.

An antenna system and a mobile terminal are provided. The antenna system includes a metal frame, a mainboard received inside the metal frame, and a first feeding point, a second feeding point, a first grounding point and a second grounding point provided on the mainboard. The metal frame includes a bottom frame separated by the breach into a first radiation portion located at the bottom left corner and a second radiation portion located at the bottom right corner. A first antenna is formed by feeding of the first feeding point, a second antenna is formed by feeding of the second feeding point, a working frequency of the first antenna covers LTE low frequency, and the working frequencies of the first antenna and the second antenna cover LTE intermediate frequency and high frequency & 3.4-3.8 GHz & C frequency band.

Techniques for tuning a crossed-field antenna are provided. An example of an antenna system includes a D-plate with a D-plate feed conductor, such that the D-plate is a horizontal conductor raised above and insulated from a ground plane, an E-cylinder with an E-cylinder feed conductor, such that the E-cylinder is a vertical hollow conductive cylinder of smaller diameter than the D-plate, which is mounted concentrically above and insulated from the D-plate, a transmitter tuning circuit configured to receive a signal from a transmitter, an E-cylinder tuning circuit operably coupled to the transmitter tuning circuit and the E-cylinder feed conductor, and a D-plate tuning circuit operably coupled to the transmitter tuning circuit and the D-plate feed conductor.

Techniques for tuning a crossed-field antenna are provided. An example of an antenna system includes a D-plate with a D-plate feed conductor, such that the D-plate is a horizontal conductor raised above and insulated from a ground plane, an E-cylinder with an E-cylinder feed conductor, such that the E-cylinder is a vertical hollow conductive cylinder of smaller diameter than the D-plate, which is mounted concentrically above and insulated from the D-plate, a transmitter tuning circuit configured to receive a signal from a transmitter, an E-cylinder tuning circuit operably coupled to the transmitter tuning circuit and the E-cylinder feed conductor, and a D-plate tuning circuit operably coupled to the transmitter tuning circuit and the D-plate feed conductor.

A mobile device including a ground plane, a grounding branch, wherein a slot is formed between the ground plane and the grounding branch, a connecting element, wherein the grounding branch is electrically coupled through the connecting element to the ground plane and a feeding element, extending across the slot, and electrically coupled between the grounding branch and a signal source, wherein an antenna structure is formed by the grounding branch and the feeding element.

A mobile device including a ground plane, a grounding branch, wherein a slot is formed between the ground plane and the grounding branch, a connecting element, wherein the grounding branch is electrically coupled through the connecting element to the ground plane and a feeding element, extending across the slot, and electrically coupled between the grounding branch and a signal source, wherein an antenna structure is formed by the grounding branch and the feeding element.

In accordance with some embodiments, an automatically tunable mobile antenna is provided with toroidal inductors connected in series between the antenna feed point and a whip and a shunt inductor to ground at the RF input, with the inductors forming an L network impedance matching circuit having values which are in a binary sequence and which are selectively added to impedance match the whip to the output impedance of a transmitter. In accordance with some embodiments, an automatically tunable mobile antenna is provided with a variable toroidal inductor assembly connected between the antenna feed point and the whip having a variable inductance based on selective shorting and un-shorting of wire windings to impedance match the whip to the output impedance of the transmitter.

In accordance with some embodiments, an automatically tunable mobile antenna is provided with toroidal inductors connected in series between the antenna feed point and a whip and a shunt inductor to ground at the RF input, with the inductors forming an L network impedance matching circuit having values which are in a binary sequence and which are selectively added to impedance match the whip to the output impedance of a transmitter. In accordance with some embodiments, an automatically tunable mobile antenna is provided with a variable toroidal inductor assembly connected between the antenna feed point and the whip having a variable inductance based on selective shorting and un-shorting of wire windings to impedance match the whip to the output impedance of the transmitter.

An antenna includes at least one dipole antenna comprising a pair of monopole antennas each monopole antenna includes an adjustable conductive element with one end electrically combined to an inductor and another end combined to an insulator. A support structure combined to the at least one dipole antenna positions one end of each monopole at an elevation higher than the other end of the monopole.