An electronic device includes a first metal element, a second metal element, a feeding radiation element, a first radiation element, a second radiation element, a third radiation element, and a matching radiation element. The first metal element is coupled to a ground voltage. The second metal element is separated from the first metal element. The first radiation element and the second radiation element are coupled to the feeding radiation element. The third radiation element is coupled to the second metal element, and is adjacent to the first radiation element and the second radiation element. An antenna structure is formed by the feeding radiation element, the first radiation element, the second radiation element, the third radiation element, and the matching radiation element. A sensing pad is formed by the second metal element and the third radiation element.

An antenna system having a Vivaldi antenna configured to be impedance matched to antenna impedance Za at and above but not below a frequency fc; a Field-Effect-Transistor buffer coupled to the Vivaldi antenna, the length of the coupling between the antenna terminals and the buffer being of a distance much less than a wavelength at frequency fc, the buffer configured to present a high impedance at frequencies substantially <fc, the buffer output impedance further configured to be matched to a system impedance Z0 at frequencies both above and below fc.

An antenna system having a Vivaldi antenna configured to be impedance matched to antenna impedance Za at and above but not below a frequency fc; a Field-Effect-Transistor buffer coupled to the Vivaldi antenna, the length of the coupling between the antenna terminals and the buffer being of a distance much less than a wavelength at frequency fc, the buffer configured to present a high impedance at frequencies substantially <fc, the buffer output impedance further configured to be matched to a system impedance Z0 at frequencies both above and below fc.

A single-layer Wide Angle Impedance Matching (WAIM) and method for using the same are described. In one embodiment, the antenna comprises: an aperture having a plurality of antenna elements operable to radiating radio-frequency (RF) energy; and a single-layer wide angle impedance matching (WAIM) structure coupled to the aperture to provide impedance matching between the antenna aperture and free space.

A single-layer Wide Angle Impedance Matching (WAIM) and method for using the same are described. In one embodiment, the antenna comprises: an aperture having a plurality of antenna elements operable to radiating radio-frequency (RF) energy; and a single-layer wide angle impedance matching (WAIM) structure coupled to the aperture to provide impedance matching between the antenna aperture and free space.

A method of providing a single structure multiple mode antenna having a unitary body construction is described. The antenna is preferably constructed having a first inductor coil portion that is electrically connected in series with a second inductor coil portion. The antenna is constructed having a plurality of electrical connections positioned along the first and second inductor coils. A plurality of terminals facilitates connection of the electrical connections having numerous electrical connection configurations and enables the antenna to be selectively tuned to various frequencies and frequency bands.

An antenna structure includes a first antenna radiator, a second antenna radiator, and a first impedance matching circuit. The first antenna radiator and the second antenna radiator are disposed in a laminated or opposite manner, and a gap exists between the first antenna radiator and the second antenna radiator. The length of the first antenna radiator is greater than that of the second antenna radiator, and the resonant frequency band of the first antenna radiator is smaller than that of the second antenna radiator. The first end of the first antenna radiator is grounded, a first feeding point is provided on the first antenna radiator. The first end of the second antenna radiator is grounded, a second feeding point is provided on the second antenna radiator, and the second feeding point is connected to a second signal source.

An antenna structure includes a first antenna radiator, a second antenna radiator, a first impedance matching circuit, a second impedance matching circuit, and a signal source, wherein the first antenna radiator is coupled to the second antenna radiator by means of a slot; the end of the first antenna radiator away from the slot is grounded, and the first antenna radiator is provided with a feed point, the end of the second antenna radiator away from the slot is grounded; a first end of the first impedance matching circuit is connected to the feed point, and a second end of the first impedance matching circuit is connected to a first end of the signal source; a first end of the second impedance matching circuit is connected to a third end of the first impedance matching circuit, and a second end of the second impedance matching circuit is grounded.

An antenna device includes a radiating element, a coupling circuit, and a non-radiating resonant circuit. The coupling circuit includes first and second coupling elements, the first coupling element being connected between a feeder circuit and the radiating element, the second coupling element being coupled to the first coupling element. An end of the second coupling element is grounded, and another end of the second coupling element is connected to the non-radiating resonant circuit. A frequency characteristic of a return loss of the radiating element when seen from the feeder circuit is adjusted by a resonant frequency characteristic of the non-radiating resonant circuit.

An antenna device includes a radiating element, a coupling circuit, and a non-radiating resonant circuit. The coupling circuit includes first and second coupling elements, the first coupling element being connected between a feeder circuit and the radiating element, the second coupling element being coupled to the first coupling element. An end of the second coupling element is grounded, and another end of the second coupling element is connected to the non-radiating resonant circuit. A frequency characteristic of a return loss of the radiating element when seen from the feeder circuit is adjusted by a resonant frequency characteristic of the non-radiating resonant circuit.