Abstract: An electronic device may be provided with first and second sidewalls, a rear wall, and a display. Multiple antenna panels may be used to convey radio-frequency signals at frequencies greater than 10 GHz. A first antenna panel may radiate through the display while second and third panels radiate through the first and second sidewalls. The second and third panels may be tilted at non-zero angles with respect to the sidewalls. The non-zero angles may be of opposite sign. The non-zero angles may have the same magnitude. The magnitude may be equal to 15 degrees, as one example. Tilting the panels in this way may allow the panels to collectively cover as much of a sphere around the device as possible, including out of coverage areas behind the rear wall caused by conductive material in the rear wall, without requiring additional panels to be disposed within the device.

Abstract: A single-switch-per-bit topology for reconfigurable reflective surfaces (RRSs) is provided. Novel multi-bit unit-cell configurations are presented for radio-frequency (RF) RRSs with improved radiation efficiency and compact designs. Embodiments described herein realize a multi-bit RRS using an antenna array with multiple integrated switches at the ports of every antenna element (e.g., one at each port, providing one control bit per switch). By manipulating the states of the switches, the impinging waves on the surface are modulated, leading to beamforming in the desired direction. Some embodiments utilize a single switch-per-bit topology integrating single-pole-single-throw (SPST) switches (e.g., PIN diodes) into the unit-cell design, achieving up to 4 bits of phase quantization with only 4 switches. The exhibited radiation efficiency of the multi-bit RRS is significantly improved compared to lower bit configurations.

Abstract: An electronic device may be provided with a phased antenna array that radiates at a frequency greater than 10 GHz. The array may include a dielectric resonator antenna having a dielectric column with non-planar sidewalls that include planar portions and corrugated portions with grooves and ridges, that include sidewall steps, and/or that include angled sidewall portions. The dielectric resonator antenna may include a first dielectric column and a second dielectric column stacked on the first dielectric column. The second column may be narrower and may have a higher dielectric constant than the first column or may have the same width but a lower dielectric constant than the first column. This may serve to broaden the bandwidth of the dielectric resonator antenna relative to scenarios where the dielectric resonator antenna includes only a single dielectric resonating element having only planar sidewalls.

Abstract: An electronic device may be provided with a phased antenna array that radiates at a frequency greater than 10 GHz. The array may include a first set of dielectric resonator antennas arranged in a first row and a second set of dielectric resonator antennas in a second row offset from the first row. Each dielectric resonator antenna may have dielectric resonating element with a base portion and a stepped portion. The stepped portions of the antennas in the first set may be arranged to be distant from the stepped portions of the antennas in the second set. The antennas in the first set may be arranged to be more distant from an electronic device sidewall than the antennas in the second set. Configured in this manner, the array may exhibit reduced inter-coupling between dielectric resonator antennas in the first set and dielectric resonator antennas in the second set.

Abstract: An electronic device may include an antenna and a coaxial cable coupled to the antenna. The coaxial cable may have a signal conductor coupled to an antenna resonating element of the antenna and a ground conductor coupled to an antenna ground of the antenna. The ground conductor may include an ungrounded segment that is separated from the antenna ground by a gap. A capacitive coupling between the ground conductor in the ungrounded segment and the antenna ground via the gap may form an impedance matching component for the coaxial cable. A dielectric retention layer may overlap the coaxial cable and hold the coaxial cable in place relative to the antenna ground to maintain the gap.

Abstract: An electronic device may be provided with a phased antenna array having a dielectric resonator antenna. The antenna may include a first dielectric block on a printed circuit, a second dielectric block on the first dielectric block, and a third dielectric block on the second dielectric block. At least the second and third dielectric blocks may have different dielectric constants. The antenna may be fed by one or more feed probes. Each feed probe may include respective conductive via and a conductive patch coupled to the conductive via. The conductive via may extend through the first dielectric block. The conductive patch may be sandwiched between the first and second dielectric blocks. The conductive patch may have a width that configures the conductive patch to form a smooth impedance transition between the conductive via and each of the dielectric blocks despite the different materials used to form the antenna.

Abstract: An electronic device may be provided with a phased antenna array having a dielectric resonator antenna. The antenna may include a first dielectric block on a printed circuit, a second dielectric block on the first dielectric block, and a third dielectric block on the second dielectric block. At least the second and third dielectric blocks may have different dielectric constants. A parasitic element may be disposed between the second and third dielectric resonating elements and/or a parasitic element may be disposed on a radiative face of the third dielectric resonating element. The parasitic elements may act as electromagnetic mirrors that form images of electric fields in the dielectric resonating elements. The images may make the dielectric resonating elements exhibit a greater electromagnetic height than physical height. This may allow for a reduction in the overall physical height of the dielectric resonator antenna without sacrificing wireless performance.

Abstract: An electronic device may be provided with first and second sidewalls, a rear wall, and a display. Multiple antenna panels may be used to convey radio-frequency signals at frequencies greater than 10 GHz. A first antenna panel may radiate through the display while second and third panels radiate through the first and second sidewalls. The second and third panels may be tilted at non-zero angles with respect to the sidewalls. The non-zero angles may be of opposite sign. The non-zero angles may have the same magnitude. The magnitude may be equal to 15 degrees, as one example. Tilting the panels in this way may allow the panels to collectively cover as much of a sphere around the device as possible, including out of coverage areas behind the rear wall caused by conductive material in the rear wall, without requiring additional panels to be disposed within the device.

Abstract: An electronic device may be provided with a phased antenna array that radiates at a frequency greater than 10 GHz. The array may include a dielectric resonator antenna having a dielectric column with non-planar sidewalls that include planar portions and corrugated portions with grooves and ridges, that include sidewall steps, and/or that include angled sidewall portions. The dielectric resonator antenna may include a first dielectric column and a second dielectric column stacked on the first dielectric column. The second column may be narrower and may have a higher dielectric constant than the first column or may have the same width but a lower dielectric constant than the first column. This may serve to broaden the bandwidth of the dielectric resonator antenna relative to scenarios where the dielectric resonator antenna includes only a single dielectric resonating element having only planar sidewalls.

Abstract: Terahertz wave plethysmography provides a new principle of radar-based vital sign detection. This disclosure presents new applications at terahertz (THz) frequency band for non-contact cardiac sensing. For the first time, cardiac pulse information is shown to be simultaneously extracted based on two established principles using unique THz waves. A novel concept of Terahertz-Wave-Plethysmography (TPG) is introduced, which detects blood volume changes in the upper dermis tissue layer by measuring the reflectance of THz waves, similar to the existing remote photoplethysmography (rPPG) principle. A detailed analysis of pulse measurement using THz is provided. The TPG principle is justified by scientific deduction and carefully designed experimental demonstrations. Additionally, pulse measurements from various peripheral body regions of interest (ROIs), including palm, inner elbow, temple, fingertip, and forehead, are demonstrated using a novel ultra-wideband (UWB) THz sensing system.

Abstract: A single-switch-per-bit topology for reconfigurable reflective surfaces (RRSs) is provided. Novel multi-bit unit-cell configurations are presented for radio-frequency (RF) RRSs with improved radiation efficiency and compact designs. Embodiments described herein realize a multi-bit RRS using an antenna array with multiple integrated switches at the ports of every antenna element (e.g., one at each port, providing one control bit per switch). By manipulating the states of the switches, the impinging waves on the surface are modulated, leading to beamforming in the desired direction. Some embodiments utilize a single switch-per-bit topology integrating single-pole-single-throw (SPST) switches (e.g., PIN diodes) into the unit-cell design, achieving up to 4 bits of phase quantization with only 4 switches. The exhibited radiation efficiency of the multi-bit RRS is significantly improved compared to lower bit configurations.

Abstract: Methods, apparatuses, systems, and implementations of an ultra-compact RF (30 GHz-10 THz) imaging sensor topology that provides a new insight into the human skin are disclosed. The skin tissue is the largest organ in the body—both in weight and surface area—and stores valuable information that can revolutionize security biometrics and mobile health monitoring. The proposed compact sensor enables, for the first time, portable and wearable devices to perform superior biometric authentication compared to current fingerprint methods. Additionally, these devices could probe into the skin to monitor vital signs in real-time and enable mobile health monitoring.

Abstract: Methods, apparatuses, systems, and implementations of an ultra-compact RF (30 GHz-10 THz) imaging sensor topology that provides a new insight into the human skin are disclosed. The skin tissue is the largest organ in the body—both in weight and surface area—and stores valuable information that can revolutionize security biometrics and mobile health monitoring. The proposed compact sensor enables, for the first time, portable and wearable devices to perform superior biometric authentication compared to current fingerprint methods. Additionally, these devices could probe into the skin to monitor vital signs in real-time and enable mobile health monitoring.