An antenna device includes an antenna element, which is able to transmit and receive high-frequency signals of a plurality of frequency bands, and an antenna matching circuit. The antenna matching circuit includes an impedance converting circuit, which is connected to the antenna element side of the circuit, and a variable reactance circuit, which is connected to a feeder circuit side of the circuit. The impedance converting circuit includes a first inductance element and a second inductance element, which are transformer coupled with each other. The variable reactance circuit includes a reactance element, which is connected in parallel or series with the transmission/reception signal transmission path, and a switch that switches the connection state of the reactance element.

An antenna including a substrate formed of a non-conductive material, a ground plane disposed on the substrate, a wideband radiating element having one end connected to an edge of the ground plane and an elongate feed arm feeding the wideband radiating element and having a maximum width of 1/100 of a predetermined wavelength, the predetermined wavelength being defined by formula (I) wherein .sub.p is the predetermined wavelength, f is a lowest operating frequency of the wideband radiating element, is a permeability of the substrate, .sub.r is a relative bulk permittivity of the substrate, W is a width of a conductive trace disposed above the substrate and H is a thickness of the substrate, wherein formula (II).

An antenna including a substrate formed of a non-conductive material, a ground plane disposed on the substrate, a wideband radiating element having one end connected to an edge of the ground plane and an elongate feed arm feeding the wideband radiating element and having a maximum width of 1/100 of a predetermined wavelength, the predetermined wavelength being defined by formula (I) wherein .sub.p is the predetermined wavelength, f is a lowest operating frequency of the wideband radiating element, is a permeability of the substrate, .sub.r is a relative bulk permittivity of the substrate, W is a width of a conductive trace disposed above the substrate and H is a thickness of the substrate, wherein formula (II).

This disclosure is directed to broadband notch antennas. In one aspect, a notch antenna includes a dielectric plate having a first surface and a second surface located opposite the first surface. A conductive layer is disposed on the first surface and has a notch region that exposes the dielectric plate between edges of the conductive layer. The antenna also includes two or more frequency matching circuits that branch from the notch region. Each matching circuit is configured to send and receive electromagnetic radiation in a frequency band of a radio spectrum.

This disclosure is directed to broadband notch antennas. In one aspect, a notch antenna includes a dielectric plate having a first surface and a second surface located opposite the first surface. A conductive layer is disposed on the first surface and has a notch region that exposes the dielectric plate between edges of the conductive layer. The antenna also includes two or more frequency matching circuits that branch from the notch region. Each matching circuit is configured to send and receive electromagnetic radiation in a frequency band of a radio spectrum.

An antenna system mounted on a vehicle according to the present invention may comprise: a first circuit board configured to be mountable to a metal frame; a second circuit board disposed so as to be spaced apart a predetermined distance from the first circuit board through a metal supporter; and an antenna configured to emit a signal transmitted from a power supply unit, said signal being transmitted through a space between the first circuit board and the second circuit board.

An antenna system mounted on a vehicle according to the present invention may comprise: a first circuit board configured to be mountable to a metal frame; a second circuit board disposed so as to be spaced apart a predetermined distance from the first circuit board through a metal supporter; and an antenna configured to emit a signal transmitted from a power supply unit, said signal being transmitted through a space between the first circuit board and the second circuit board.

The present invention relates to a parallel-feeding, dual-band and dual-polarized base station antenna comprising a radiating patch layer, four F-shaped metal strips which are perpendicular to the radiating patch layer and orthogonal to each other, and a feeding layer, which is sequentially disposed from top to bottom, wherein the radiating patch layer comprises the first metal covering layer and the first dielectric layer; wherein the first metal covering layer is square-shaped and an isosceles triangle having the same size is cut from each corner of the square; wherein the four F-shaped metal strips work as the extended part of the feeding layer to couple-feed the radiating patch layer; the feeding layer comprises the first metal feed-line layer, the second dielectric layer, the metal floor layer, the third dielectric layer and the second metal feed-line layer, which are sequentially disposed from top to bottom.

The present invention relates to a parallel-feeding, dual-band and dual-polarized base station antenna comprising a radiating patch layer, four F-shaped metal strips which are perpendicular to the radiating patch layer and orthogonal to each other, and a feeding layer, which is sequentially disposed from top to bottom, wherein the radiating patch layer comprises the first metal covering layer and the first dielectric layer; wherein the first metal covering layer is square-shaped and an isosceles triangle having the same size is cut from each corner of the square; wherein the four F-shaped metal strips work as the extended part of the feeding layer to couple-feed the radiating patch layer; the feeding layer comprises the first metal feed-line layer, the second dielectric layer, the metal floor layer, the third dielectric layer and the second metal feed-line layer, which are sequentially disposed from top to bottom.

A broadband blade monopole antenna is disclosed. The broadband blade monopole antenna includes a body portion that is substantially flat to define a two-dimensional plane that the body portion extends along. The body portion defines an outer perimeter having four sides. The four sides are grouped into two pairs of equal-length sides positioned directly adjacent to each other. The broadband blade monopole antenna provides at least about 100% impedance bandwidth.