An antenna structure includes a substrate, a first radiating element, a second radiating element, a first inductor, a ground element, a first conducting element and a feeding element. The first radiating element is disposed on the substrate. The second radiating element is disposed on the substrate. The second radiating element includes a feed receiving portion. The first inductor is coupled between the first radiating element and the second radiating element. The first conducting element is coupled between the feed receiving portion and the ground element. The feeding element is coupled between the feed receiving portion and the ground element and for feeding in a signal.

The present disclosure includes a first circuit that is connected between a power feed port and an antenna port, and a second circuit that is connected between the power feed port and the ground or between the antenna port and the ground. The first circuit is a circuit in which for example a first variable capacitance element is connected in series with a first inductor, and the second circuit is a circuit in which for example a second variable capacitance element is connected in parallel with a second inductor. A switch performs switching at least between a first state in which a second end of the second circuit is connected to a first end of the first circuit and a second state in which the second end of the second circuit is connected to a second end of the first circuit.

The present disclosure includes a first circuit that is connected between a power feed port and an antenna port, and a second circuit that is connected between the power feed port and the ground or between the antenna port and the ground. The first circuit is a circuit in which for example a first variable capacitance element is connected in series with a first inductor, and the second circuit is a circuit in which for example a second variable capacitance element is connected in parallel with a second inductor. A switch performs switching at least between a first state in which a second end of the second circuit is connected to a first end of the first circuit and a second state in which the second end of the second circuit is connected to a second end of the first circuit.

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.

A feed for a dual-band antenna, comprising: a first waveguide for low frequency electromagnetic radiations, a second dielectric waveguide for high frequency electromagnetic radiations, an end connected to a low band port configured to pass said low frequency electromagnetic radiations, and a high band port configured to pass said high frequency electromagnetic radiations,
wherein the first waveguide comprises a first longitudinal section and a second longitudinal section, wherein a minimal distance between an internal surface of walls of the first section and an external surface of walls of the second dielectric waveguide is D.sub.11 along a lateral direction orthogonal to the longitudinal direction, and wherein a maximal distance between an internal surface of at least one first wall of the second section and an external surface of a wall of the second dielectric waveguide facing said first wall is D.sub.12 along said lateral direction, wherein D.sub.12<D.sub.11.

A feed for a dual-band antenna, comprising: a first waveguide for low frequency electromagnetic radiations, a second dielectric waveguide for high frequency electromagnetic radiations, an end connected to a low band port configured to pass said low frequency electromagnetic radiations, and a high band port configured to pass said high frequency electromagnetic radiations,
wherein the first waveguide comprises a first longitudinal section and a second longitudinal section, wherein a minimal distance between an internal surface of walls of the first section and an external surface of walls of the second dielectric waveguide is D.sub.11 along a lateral direction orthogonal to the longitudinal direction, and wherein a maximal distance between an internal surface of at least one first wall of the second section and an external surface of a wall of the second dielectric waveguide facing said first wall is D.sub.12 along said lateral direction, wherein D.sub.12<D.sub.11.

A dual-polarized omnidirectional antenna, which includes a vertically polarized antenna and a loop horizontally polarized antenna. The vertically polarized antenna includes a vertical fixed cover and a cylindrical antenna which is fixedly mounted in the vertical fixed cover. The horizontally polarized antenna includes a horizontal fixed cover and a loop antenna which is fixedly mounted in the horizontal fixing cover. The vertical fixed cover is fixedly mounted on the horizontal fixed cover. The cylindrical antenna receives the vertically polarized signal, and the loop antenna receives the horizontally polarized signal. The loop antenna can also receive the horizontally polarized signal omnidirectionally at the same time to ensure a better receiving effect.

An RFID tag device with an RFID antenna assembly that increases transmission range of the RFID tag device when adhesively coupled to a mobile device. The RFID tag device includes a RF interface that operates at a first RF frequency, a controller coupled to the RF interfaces, and the RFID antenna assembly. The RFID antenna assembly includes a first and a second dipole elements, each shaped as a half rectangle with an additional segment joining the respective element to a tuning element. The RFID antenna also includes a tuning element, which is a loop antenna, connecting the RF interface to the controller and a ferrite dielectric on the back of one of the dipole elements. A structure of the RF antennal assembly, when the RFID tag device is coupled to a mobile device, causes the mobile device to function as a reflector to increase gain of the RFID antenna assembly thereby improving transmission range.

An RFID tag device with an RFID antenna assembly that increases transmission range of the RFID tag device when adhesively coupled to a mobile device. The RFID tag device includes a RF interface that operates at a first RF frequency, a controller coupled to the RF interfaces, and the RFID antenna assembly. The RFID antenna assembly includes a first and a second dipole elements, each shaped as a half rectangle with an additional segment joining the respective element to a tuning element. The RFID antenna also includes a tuning element, which is a loop antenna, connecting the RF interface to the controller and a ferrite dielectric on the back of one of the dipole elements. A structure of the RF antennal assembly, when the RFID tag device is coupled to a mobile device, causes the mobile device to function as a reflector to increase gain of the RFID antenna assembly thereby improving transmission range.