Abstract: An electronic device housing may have a rear housing wall that forms a metal ground plane. A slot may be formed in the metal ground plane. The slot may have one or more open ends along an edge of the ground plane. A near-field communications loop antenna may overlap the slot. The near-field communications loop antenna may have one or more turns. A current path through the metal ground plane may form one of the turns in the near-field communications loop antenna. The slot may form portions of non-near-field-communications antennas in addition to the near-field communications loop antenna. The slot in the non-near-field-communications antennas may be fed using an indirect antenna feed structure. Components such as a capacitor and inductor may help allow non-near-field communications antenna and the near-field communications antenna to be formed from common portions of the metal ground plane.

Abstract: An electronic device may have hybrid antennas that include slot antenna resonating elements formed from slots in a ground plane and planar inverted-F antenna resonating elements. The planar inverted-F antenna resonating elements may each have a planar metal member that overlaps one of the slots. The slot of each slot antenna resonating element may divide the ground plane into first and second portions. A return path and feed may be coupled in parallel between the planar metal member and the first portion of the ground plane. Tunable components such as tunable inductors may be used to tune the hybrid antennas. A tunable inductor may bridge the slot in hybrid antenna, may be coupled between the planar metal member of the planar inverted-F antenna resonating element and the ground plane, or multiple tunable inductors may bridge the slot on opposing sides of the planar inverted-F antenna resonating element.

Abstract: Low-profile broadband patch antennas capable of radiating circularly polarized (CP) signals utilizing a single probe in accordance with embodiments of the invention are disclosed. In many embodiments, the patch antenna includes a ground plane, a patch plate, at least one dielectric or foam substrate, and a feed probe. In several embodiments, the patch plate includes a first plate and a second plate that can be connected via first and second connecting bars. In various embodiments, the connection of the first and second plates can expose first and second slots as further discussed below. In a variety of embodiments, the feed probe can be a coaxial cable having an inner and outer conductor where the inner conductor connects to the first plate and the outer conductor connects to the ground plane.

Abstract: An electronic device may be provided with a conductive wall. A gap in the wall may divide the wall into first and second segments. A ground may be separated from the wall by first, second, and third slots that form radiating elements for first, second, and third non-near-field communications antennas. First and second conductive structures may be coupled between the wall and the ground. A near-field communications antenna may include a first feed terminal coupled to the first segment and a second feed terminal coupled to the second segment. The antenna may convey signals over a conductive loop path that includes portions of the first and second segments, the antenna ground, and the first and second conductive structures. A differential or single-ended signal transmission line may be coupled to the terminals. Phase shifters may configure the signals to be out of phase at the feed terminals.

Abstract: An electronic device may have conductive housing structures and first, second, third, and fourth slot antennas having respective first, second, third, and fourth slot elements in the conductive housing structures. The third slot element may be interposed between the first and second slot elements and the second slot element may be interposed between the third and fourth slot elements. Switching circuitry may be coupled between a transceiver and the slot elements. Control circuitry may control the switching circuitry to activate a selected pair of the slot antennas based on an orientation of the device or other data. The active pair of antennas may convey radio-frequency signals at the same frequencies using a multiple-input and multiple-output (MIMO) communications scheme. In this way, the device may perform wireless communications at relatively high data throughputs regardless of how the device is being held by a user.

Abstract: An electronic device may have a hybrid antenna that includes a slot resonating element formed from a slot in a ground plane and a planar resonating element formed over the slot. A parasitic element may be disposed over the planar element. A switch may couple the parasitic element to the ground. A tunable circuit may couple the planar element to the ground. The switch and tunable circuit may be placed in different tuning states. In a first state, the tunable circuit and switch form open circuits. In a second state, the tunable circuit may an open circuit and the switch is closed. In a third state, the tunable circuit forms a return path and the switch forms an open circuit. This may allow the antenna to operate with satisfactory efficiency in low, mid, and high bands despite volume constraints imposed on the antenna.

Abstract: An electronic device may include a metal housing and a distributed loop antenna. The antenna may include a dielectric carrier. The antenna may include a distributed loop antenna resonating element that extends around the carrier and a loop antenna feed element on the carrier. Portions of the feed element and loop antenna resonating element may be formed from the housing. The feed element may be directly fed and may indirectly feed the distributed loop antenna resonating element via near field electromagnetic coupling. The loop antenna resonating element may include a conductive sheet on the carrier. The conductive sheet and the housing may form a conductive loop path of the loop antenna resonating element. A capacitance may be interposed in the conductive loop path and may be formed by a gap between the conductive sheet and the housing. A speaker driver may be placed within a cavity in the carrier.

Abstract: An electronic device may have hybrid antennas that include slot antenna resonating elements formed from slots in a ground plane and planar inverted-F antenna resonating elements. The planar inverted-F antenna resonating elements may each have a planar metal member that overlaps one of the slots. A return path and feed may be coupled in parallel between the planar metal member and the ground plane. Adjustable circuits such as tunable inductors may be used to tune the hybrid antennas. Adjustable circuits may bridge the slots in hybrid antennas and may be included in return paths that are coupled between the planar metal members of the planar inverted-F antenna resonating elements and the ground plane. A slot may be selectively divided to from two slots using switching circuitry.

Abstract: An electronic device may be provided with antennas. Antennas for the electronic device may be formed from slot antenna structures. A slot antenna structure may be formed from portions of a metal housing for an electronic device. The slots of the slot antenna structures may be indirectly fed to form first and second indirectly fed slot antennas. The first and second indirectly fed slot antennas may be formed from slots in a rear surface of an electronic device and a sidewall of the electronic device. The slots may have open ends along an edge of the sidewall and may have closed ends that face each other. A hybrid antenna may also be formed in the electronic device.

Abstract: Low-profile broadband patch antennas capable of radiating circularly polarized (CP) signals utilizing a single probe in accordance with embodiments of the invention are disclosed. In many embodiments, the patch antenna includes a ground plane, a patch plate, at least one dielectric or foam substrate, and a feed probe. In several embodiments, the patch plate includes a first plate and a second plate that can be connected via first and second connecting bars. In various embodiments, the connection of the first and second plates can expose first and second slots as further discussed below. In a variety of embodiments, the feed probe can be a coaxial cable having an inner and outer conductor where the inner conductor connects to the first plate and the outer conductor connects to the ground plane.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include cavity antennas. A cavity antenna may be formed from a metal antenna cavity and resonating element structures. The metal antenna cavity may be formed from metal traces on a dielectric carrier. The resonating element structures may include directly fed and indirectly fed slot antenna resonating elements and monopole antenna resonating elements. The metal antenna cavity may exhibit a resonance that is tuned using a transmission line tuning stub. Filters and duplexer circuits may be used in routing signals at different frequency bands among the antenna resonating elements.

Abstract: An electronic device may have hybrid antennas that include slot antenna resonating elements formed from slots in a ground plane and planar inverted-F antenna resonating elements. The planar inverted-F antenna resonating elements may each have a planar metal member that overlaps one of the slots. The slot of each slot antenna resonating element may divide the ground plane into first and second portions. A return path and feed may be coupled in parallel between the planar metal member and the first portion of the ground plane. Tunable components such as tunable inductors may be used to tune the hybrid antennas. A tunable inductor may bridge the slot in hybrid antenna, may be coupled between the planar metal member of the planar inverted-F antenna resonating element and the ground plane, or multiple tunable inductors may bridge the slot on opposing sides of the planar inverted-F antenna resonating element.

Abstract: An electronic device housing may have a rear housing wall that forms a metal ground plane. A slot may be formed in the metal ground plane. The slot may have one or more open ends along an edge of the ground plane. A near-field communications loop antenna may overlap the slot. The near-field communications loop antenna may have one or more turns. A current path through the metal ground plane may form one of the turns in the near-field communications loop antenna. The slot may form portions of non-near-field-communications antennas in addition to the near-field communications loop antenna. The slot in the non-near-field-communications antennas may be fed using an indirect antenna feed structure. Components such as a capacitor and inductor may help allow non-near-field communications antenna and the near-field communications antenna to be formed from common portions of the metal ground plane.

Abstract: An electronic device may be provided with a satellite positioning system slot antenna. The slot antenna may include a slot in a metal housing. The slot may be directly fed or indirectly fed. In indirectly fed configurations, the antenna may include a near-field-coupled antenna feed structure that is near-field coupled to the slot. The near-field-coupled antenna feed structure may be formed from a planar metal structure. The planar metal structure may be a metal patch that overlaps the slot and that has a leg that protrudes towards the metal housing. A positive antenna feed terminal may be coupled to the leg and a ground antenna feed terminal may be coupled to the metal housing.

Abstract: An electronic device may include balance-fed antenna structures that do not have direct paths to ground. The antenna structures may serve as a Global Positioning System (GPS) antenna and may have a dipole structure having a first and second antenna resonating element arms. The antenna structures may include a conductive path that conveys antenna signals between a first feed terminal on the first antenna resonating element arm and a transmission line. The conductive path may overlap with the second antenna resonating element arm such that current flow through the conductive path induces corresponding current flow in the second antenna resonating element arm. The antenna structures may include an impedance matching short-circuit stub path that couples the first antenna resonating element arm to the second antenna resonating element arm. Choke inductors may be used to help block indirect paths from the antenna structures to ground through adjacent circuitry.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include cavity antennas. A cavity antenna may be formed from a metal antenna cavity and resonating element structures. The metal antenna cavity may be formed from metal traces on a dielectric carrier. The resonating element structures may include directly fed and indirectly fed slot antenna resonating elements and monopole antenna resonating elements. The metal antenna cavity may exhibit a resonance that is tuned using a transmission line tuning stub. Filters and duplexer circuits may be used in routing signals at different frequency bands among the antenna resonating elements.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include a pair of antennas. The antennas may be formed from inverted-F antenna resonating elements located along one of the peripheral edges of a device housing. The housing may be formed of metal and may serve as an antenna ground for the antennas. The antennas may be used to receive satellite navigation system signals that are processed by a satellite navigation system receiver. An orientation sensor may be used to gather information on the orientation of the electronic device relative to the Earth. Information on received signal strength may be obtained from the satellite navigation system receiver. Based on orientation information or received signal strength information or other information, switching circuitry may be adjusted to switch an optimum one of the antennas into use or phase shifter circuitry may be adjusted to optimize signal reception.

Abstract: An electronic device may be provided with antennas. Antennas for the electronic device may be formed from slot antenna structures. A slot antenna structure may be formed from portions of a metal housing for an electronic device. The slots of the slot antenna structures may be indirectly fed to form first and second indirectly fed slot antennas. The first and second indirectly fed slot antennas may be formed from slots in a rear surface of an electronic device and a sidewall of the electronic device. The slots may have open ends along an edge of the sidewall and may have closed ends that face each other. A hybrid antenna may also be formed in the electronic device.

Abstract: An electronic device may be provided with a satellite positioning system slot antenna. The slot antenna may include a slot in a metal housing. The slot may be directly fed or indirectly fed. In indirectly fed configurations, the antenna may include a near-field-coupled antenna feed structure that is near-field coupled to the slot. The near-field-coupled antenna feed structure may be formed from a planar metal structure. The planar metal structure may be a metal patch that overlaps the slot and that has a leg that protrudes towards the metal housing. A positive antenna feed terminal may be coupled to the leg and a ground antenna feed terminal may be coupled to the metal housing.

Abstract: An electronic device may include balance-fed antenna structures that do not have direct paths to ground. The antenna structures may serve as a Global Positioning System (GPS) antenna and may have a dipole structure having a first and second antenna resonating element arms. The antenna structures may include a conductive path that conveys antenna signals between a first feed terminal on the first antenna resonating element arm and a transmission line. The conductive path may overlap with the second antenna resonating element arm such that current flow through the conductive path induces corresponding current flow in the second antenna resonating element arm. The antenna structures may include an impedance matching short-circuit stub path that couples the first antenna resonating element arm to the second antenna resonating element arm. Choke inductors may be used to help block indirect paths from the antenna structures to ground through adjacent circuitry.