An antenna (100) for emitting radiation from at least one electromagnetic traveling wave which propagates along a guide path is designed to reduce reflection of the traveling wave likely to occur at the end of the guide path. To this purpose, the guide path has at least one portion in the form of a spiral segment (11, 12), which is connected to another portion of the guide path in the form of a loop (13). Gain in the antenna's reflection coefficient can be obtained in this manner, which is effective in particular near a lower frequency limit of a transmission band of the antenna.

An antenna (100) for emitting radiation from at least one electromagnetic traveling wave which propagates along a guide path is designed to reduce reflection of the traveling wave likely to occur at the end of the guide path. To this purpose, the guide path has at least one portion in the form of a spiral segment (11, 12), which is connected to another portion of the guide path in the form of a loop (13). Gain in the antenna's reflection coefficient can be obtained in this manner, which is effective in particular near a lower frequency limit of a transmission band of the antenna.

An antenna and method for using the same are disclosed. In one embodiment, an antenna comprises a radial waveguide; an aperture operable to radiate radio frequency (RF) signals in response to an RF feed wave fed by the radial waveguide; and a radio frequency (RF) choke operable to block RF energy from exiting through a gap between outer portions of the waveguide and the aperture.

An antenna and method for using the same are disclosed. In one embodiment, an antenna comprises a radial waveguide; an aperture operable to radiate radio frequency (RF) signals in response to an RF feed wave fed by the radial waveguide; and a radio frequency (RF) choke operable to block RF energy from exiting through a gap between outer portions of the waveguide and the aperture.

A non-circular center-fed antenna and method for using the same are disclosed. In one embodiment, the antenna comprises: a non-circular antenna aperture with radio-frequency (RF) radiating antenna elements; and a non-radially symmetric directional coupler to supply a RF feed wave to the aperture at a central location within the antenna aperture to enable the feed wave to propagate outward from the central location to an edge of the aperture.

An antenna apparatus includes a grounding plate, a monopole, a first feeding component, and a second feeding component. A slot on the grounding plate includes a first slot and a second slot that interpenetrate each other, the second slot extends from the first slot to an edge of the grounding plate. The monopole includes a first stub and a second stub extending from the first stub to the second slot, the second stub and the second slot form a feeding structure. The first feeding component is electrically coupled to the grounding plate to feed the feeding structure to excite a first radiation mode of the antenna apparatus. The second feeding component is electrically coupled to the second stub to feed the feeding structure to excite a second radiation mode of the antenna apparatus. Polarizations in the two radiation modes are orthogonal.

An antenna apparatus includes a grounding plate, a monopole, a first feeding component, and a second feeding component. A slot on the grounding plate includes a first slot and a second slot that interpenetrate each other, the second slot extends from the first slot to an edge of the grounding plate. The monopole includes a first stub and a second stub extending from the first stub to the second slot, the second stub and the second slot form a feeding structure. The first feeding component is electrically coupled to the grounding plate to feed the feeding structure to excite a first radiation mode of the antenna apparatus. The second feeding component is electrically coupled to the second stub to feed the feeding structure to excite a second radiation mode of the antenna apparatus. Polarizations in the two radiation modes are orthogonal.

An example wireless power transmitter includes a ground plate, a conductive wire offset from the ground plate, and a signal-conveyance member. The conductive wire of the wireless power transmitter forms a loop antenna that is configured to radiate a radio frequency (RF) signal for wirelessly powering a receiver device. And the signal-conveyance member of the wireless power transmitter is configured to selectively feed a waveform to a connection point of a plurality of connection points along the conductive wire, wherein the waveform, when provided to the conductive wire, causes the loop antenna to radiate the RF signal.

Disclosed is a radar antenna including an antenna body including a first plate and a second plate; a slot radiation part and a slot reception part formed in the first plate; a transmission port and a reception port formed in the second plate; and a waveguide formed by assembling the first and second plates. The slot radiation part includes a first slot radiation part configured to radiate a radio wave in a first detection range, and a second slot radiation part configured to radiate radio waves in a second detection range having a larger width and distance than the first detection range.

Disclosed is a radar antenna including an antenna body including a first plate and a second plate; a slot radiation part and a slot reception part formed in the first plate; a transmission port and a reception port formed in the second plate; and a waveguide formed by assembling the first and second plates. The slot radiation part includes a first slot radiation part configured to radiate a radio wave in a first detection range, and a second slot radiation part configured to radiate radio waves in a second detection range having a larger width and distance than the first detection range.