An electronic device may be provided with an antenna for receiving signals in first and second ultra-wideband communications bands. The antenna may include a shielding ring that runs around first and second arms. The first arm may radiate in the first band and the second arm may radiate in the second band. The first arm may have an end formed from a first segment of the ring and a radiating edge facing the second arm. The second arm may have an end formed from a second segment of the ring and a radiating edge facing the first arm. First and second sets of conductive vias may couple the ring to ground. The first set may form a return path for the first arm. The second set may form a return path for the second arm.

An electronic device includes: an interface circuit; and a first instance of an antenna having a radiator and multiple sets of reflectors and directors arranged along different axes passing through the radiator in a horizontal plane. A given set of reflectors and directors includes a given reflector and a given director on opposite sides of the radiator and along a given axis. During operation, the interface circuit provides control signals to switching elements that selectively electrically couple the one or more of the reflectors, one or more of the directors, or both to ground, where the one or more of the reflectors, one or more of the directors, or both modify an antenna radiation pattern of the radiator. Then, the interface circuit communicates, via the first instance of the antenna, a packet or a frame with a second electronic device.

An electronic device may be provided with an antenna for receiving signals in first and second ultra-wideband communications bands. The antenna may include a shielding ring that runs around first and second arms. The first arm may radiate in the first band and the second arm may radiate in the second band. The first arm may have an end formed from a first segment of the ring and a radiating edge facing the second arm. The second arm may have an end formed from a second segment of the ring and a radiating edge facing the first arm. First and second sets of conductive vias may couple the ring to ground. The first set may form a return path for the first arm. The second set may form a return path for the second arm.

The present disclosure relates to systems for providing wireless power to implanted devices. Consistent with some embodiments, an antenna system for providing wireless power to an implanted device includes a primary antenna loop and at least one parasitic antenna loop. The primary antenna loop is configured to receive power from a power source and radiate the power toward the implanted device. The at least one parasitic antenna loop is configured to absorb a portion of the radiated power and to reradiate the absorbed power toward the implanted device. The power radiated by the primary antenna loop and the power reradiated by the at least one parasitic antenna loop form a wireless power transmission pattern broadly distributed at the surface of the individual's skin and becomes more focused as it travels into the individual's body toward the implanted device. The broad distribution pattern at the surface of the skin reduces the specific absorption rate of the transmission while focusing the transmission as it toward the implanted device improves the antenna system's transfer efficiency.

The disclosed structures and methods are directed to antenna systems configured to transmit and receive a wireless signal in and from different directions. A switchable lens antenna has excitation ports radiating radio-frequency (RF) wave into a parallel-plate waveguide structure, and a frequency selective structure (FSS). The antenna presented herein is configured to operate in two modes depending on an initial steering angle of the RF wave propagating in the parallel-plate waveguide structure. When the initial steering angle is about or less than a threshold steering angle, FSS is OFF due to its stubs being electrically disconnected from the parallel-plate waveguide structure. When the initial steering angle is higher than the threshold, FSS is ON with stubs being electrically connected to the parallel-plate waveguide structure. When ON, FSS provides phase variance to the RF wave propagating in the parallel-plate waveguide structure and increases steering angle of the RF wave.

The disclosed structures and methods are directed to antenna systems configured to transmit and receive a wireless signal in and from different directions. A switchable lens antenna has excitation ports radiating radio-frequency (RF) wave into a parallel-plate waveguide structure, and a frequency selective structure (FSS). The antenna presented herein is configured to operate in two modes depending on a steering angle of the RF wave propagating in the parallel-plate waveguide structure. When the steering angle is about or less than a threshold steering angle, FSS is OFF due to its stubs being electrically disconnected from the parallel-plate waveguide structure. When the steering angle is higher than the threshold, FSS is ON with stubs being electrically connected to the parallel-plate waveguide structure. When ON, FSS provides phase variance to the RF wave propagating in the parallel-plate waveguide structure and increases steering angle of the RF wave.

An antenna system comprises an antenna array having a plurality of antenna elements each having a resonator configured for emitting non-optical radiation, and a resonance tuning device for tuning a resonance frequency of the resonator. The antenna system also comprises an optical array having a plurality of light activated devices respectively aligned with the plurality of antenna elements, and a network of waveguides arranged to guide light to each light activated device. Each activated device provides electrical energy to a respective resonance tuning device upon activation by light via a respective waveguide.

A method for operating an electromagnetic compatibility testing system includes for selected frequencies, adjusting incrementally the lengths of each of the plurality of length-adjustable elements for selected combinations of length ratios between the driven element and other length-adjustable elements, including length ratios where the driven element is longer than the other length-adjustable elements, for each selected frequency storing in a table one of the incremental lengths at one of the selected combinations of length ratios having one of the lowest VSWR and a VSWR lower than a threshold value that has highest signal strength, for each selected frequency adjusting the lengths of each of the length-adjustable elements to the stored lengths, driving RF energy at the selected frequency at a EMC test power level into the EMC antenna generating an e-field in the equipment under test, and measuring behavior of the equipment under test in the presence of the e-field.

A method for operating an electromagnetic compatibility testing system includes for selected frequencies, adjusting incrementally the lengths of each of the plurality of length-adjustable elements for selected combinations of length ratios between the driven element and other length-adjustable elements, including length ratios where the driven element is longer than the other length-adjustable elements, for each selected frequency storing in a table one of the incremental lengths at one of the selected combinations of length ratios having one of the lowest VSWR and a VSWR lower than a threshold value that has highest signal strength, for each selected frequency adjusting the lengths of each of the length-adjustable elements to the stored lengths, driving RF energy at the selected frequency at a EMC test power level into the EMC antenna generating an e-field in the equipment under test, and measuring behavior of the equipment under test in the presence of the e-field.

Aspect of the present disclosure are directed to methods and apparatus producing enhanced radiation characteristics, e.g., wideband behavior, in or for antennas and related components by providing concentric sleeves, with air or dielectric material as a spacer, where the sleeves include one or more conductive layers, at least a portion of which includes fractal resonators closely spaced, in terms of wavelength. A further aspect of the present disclosure is directed to surfaces that include dual-use or multiple-use apertures. Such aperture engine surfaces can include a first layer of antenna arrays, a second layer including a metal-fractal backplane player, and a third layer including solar cells for solar cell or solar oriented power collection. Fractal metamaterial ribbons with multiple closely-packed fractal resonators are also disclosed.