Abstract: A switchable antenna comprises an RF port, an antenna array that includes at least a first column of radiating elements, a second column of radiating elements and a third column of radiating elements, and a feed network coupled between the RF port and the antenna array. The feed network includes a first switch having a first output that is coupled to each of the columns of radiating elements and a second output and a second switch having a first input coupled to the first output of the first switch and a second input coupled to the second output of the first switch, and a first output coupled to the second column of radiating elements.

Abstract: An antenna comprises a printed circuit board that includes a central feed point and a plurality of antenna elements formed therein, where the antenna elements extending radially from the central feed point. Each antenna element comprises a feed line that is coupled to the central feed point, the feed line including a feed conductor and a ground conductor, and at least two dipole radiators coupled to the feed line, each dipole radiator comprising a first dipole arm that is coupled to the feed conductor and a second dipole arm that is coupled to the ground conductor. A first length of a first of the dipole radiators is different than a second length of a second of the dipole radiators. Each of the dipole radiators is fed in-phase.

Abstract: An electronic device may have wireless circuitry with antennas. The electronic device may have a dielectric housing. A printed circuit board with electrical components may be mounted in the dielectric housing. Heat spreader structures may be used to dissipate heat from the electrical components. The heat spreader structures be configured to form antenna cavities. The antennas in the electronic device may be formed from the antenna cavities and may have antenna resonating elements formed on the printed circuit. An electrical component such as a light-emitting diode may be mounted in one of the antenna cavities. Each antenna element may be an inverted-F antenna resonating element with short and long arms. The short arm of each antenna resonating element may be formed from edge plated metal traces on an edge of the printed circuit.

Abstract: An example method of designing a multi-band antenna includes specifying a first portion of the multi-band antenna in a tangible medium, where the first portion corresponds to an existing design of a single-band monopole antenna for operating in a first frequency band, and specifying in the tangible medium a second portion of the multi-band antenna that is added to the first portion, where the second portion includes a dipole parasitic resonator that is resonant in a second frequency band.

Abstract: An example method of designing a multi-band antenna includes specifying a first portion of the multi-band antenna in a tangible medium, where the first portion corresponds to an existing design of a single-band monopole antenna for operating in a first frequency band, and specifying in the tangible medium a second portion of the multi-band antenna that is added to the first portion, where the second portion includes a dipole parasitic resonator that is resonant in a second frequency band.

Abstract: An electronic device may have wireless circuitry with antennas. The electronic device may have a dielectric housing. A printed circuit board with electrical components may be mounted in the dielectric housing. Heat spreader structures may be used to dissipate heat from the electrical components. The heat spreader structures be configured to form antenna cavities. The antennas in the electronic device may be formed from the antenna cavities and may have antenna resonating elements formed on the printed circuit. An electrical component such as a light-emitting diode may be mounted in one of the antenna cavities. Each antenna element may be an inverted-F antenna resonating element with short and long arms. The short arm of each antenna resonating element may be formed from edge plated metal traces on an edge of the printed circuit.

Abstract: According to one embodiment of the invention, a network device comprises a plurality of antennas comprising a first antenna, wherein the first antenna comprises: a first set of one or more elements that form an Alford loop and that is configured for electrical excitation via a current transmitted over a conductive medium from a signal source and a second set of one or more elements that is configured for electromagnetic induction without contact with the conductive medium from the signal source.

Abstract: According to one embodiment of the invention, a network device comprises a plurality of antennas comprising a first antenna, wherein the first antenna comprises: a first set of one or more elements that form an Alford loop and that is configured for electrical excitation via a current transmitted over a conductive medium from a signal source and a second set of one or more elements that is configured for electromagnetic induction without contact with the conductive medium from the signal source.

Abstract: According to one embodiment of the invention, a network device comprises a plurality of antennas comprising a first antenna, wherein the first antenna comprises: a first set of one or more elements that form an Alford loop and that is configured for electrical excitation via a current transmitted over a conductive medium from a signal source and a second set of one or more elements that is configured for electromagnetic induction without contact with the conductive medium from the signal source.

Abstract: According to one embodiment of the invention, a network device comprises a plurality of antennas comprising a first antenna, wherein the first antenna comprises: a first set of one or more elements that form an Alford loop and that is configured for electrical excitation via a current transmitted over a conductive medium from a signal source and a second set of one or more elements that is configured for electromagnetic induction without contact with the conductive medium from the signal source.

Abstract: Electronic devices may include radio-frequency transceiver circuitry and antenna structures. The antenna structures may include antenna resonating elements, parasitic antenna resonating elements, and antenna ground structures. The antenna structures may include metal traces that are wrapped around an elongated plastic carrier. The plastic carrier may have metal traces that are coupled to a metal bracket using solder that protrudes through a hole in the metal bracket. A printed circuit board may be mounted between the metal bracket and a metal housing. The metal housing may have a protruding ridge portion that is gripped between prongs on the metal bracket. A cover may cover the metal traces on the elongated plastic carrier. The antenna structures may be mounted between hinge structures that couple upper and lower housing structures. The antenna structures may be configured to operate with comparable performance when the upper and lower housing structures are open and closed.

Abstract: A reverse RFID location system is based on set of RFID tags in which each tag stores data representing its position.

Abstract: Electronic devices may include radio-frequency transceiver circuitry and antenna structures. The antenna structures may include antenna resonating elements, parasitic antenna resonating elements, and antenna ground structures. The antenna structures may include metal traces that are wrapped around an elongated plastic carrier. The plastic carrier may have metal traces that are coupled to a metal bracket using solder that protrudes through a hole in the metal bracket. A printed circuit board may be mounted between the metal bracket and a metal housing. The metal housing may have a protruding ridge portion that is gripped between prongs on the metal bracket. A cover may cover the metal traces on the elongated plastic carrier. The antenna structures may be mounted between hinge structures that couple upper and lower housing structures. The antenna structures may be configured to operate with comparable performance when the upper and lower housing structures are open and closed.

Abstract: A reverse RFID location system is based on set of RFID tags in which each tag stores data representing its position.

Abstract: Disclosed herein is a low profile quadrifilar helix antenna system having the non-fed ends of the helix conductor arms shorted to a first ground plane, the ground plane mounted below the helix. The first ground plane is mounted perpendicularly to the central axis of the helix and extends radially outward therefrom to form an effective electromagnetic shield between the helix and adjacent ground planes. The extension of the first ground plane combined with the shorted non-fed ends of the helix arms minimize the influence of placement of the antenna system near adjacent ground conductors on the VSWR performance of the antenna. The conical frustum geometry of the helix conductors is configured to provide a low profile, resonant antenna. An integrated signal conditioning network is mounted within a cavity defined between the first ground plane and a second ground plane below the first ground plane.