The present disclosure relates to an electronic device that includes a first radiating element configured to radiate a first electromagnetic wave and a second radiating element configured to radiate a second electromagnetic wave. A first radiation pattern of the first electromagnetic wave is configured to be adjusted, and a second radiation pattern of the second electromagnetic wave is configured to be fixed.

The disclosed embodiments relate to the design of a system that implements a reflectarray antenna. The system includes a time-modulated metasurface, which is configured to act as a planar reflector for an electromagnetic wave that is radiated by a feeder into free space at an operation frequency f.sub.0. The time-modulated metasurface includes time-modulated unit-cells that provide a nonlinear conversion between f.sub.0 and another desired frequency f.sub.d. The system also includes a phase-delay mechanism, which adjusts a phase delay by acting on a phase applied to a modulation frequency f.sub.m that modulates each unit-cell. The nonlinear conversion and the phase-delay mechanism operate collectively to facilitate angle-independent nonreciprocity by imposing different phase gradients during up-conversion and down-conversion processes, and by preventing generation of certain propagative harmonics due to total internal reflection.

The disclosed embodiments relate to the design of a system that implements a reflectarray antenna. The system includes a time-modulated metasurface, which is configured to act as a planar reflector for an electromagnetic wave that is radiated by a feeder into free space at an operation frequency f.sub.0. The time-modulated metasurface includes time-modulated unit-cells that provide a nonlinear conversion between f.sub.0 and another desired frequency f.sub.d. The system also includes a phase-delay mechanism, which adjusts a phase delay by acting on a phase applied to a modulation frequency f.sub.m that modulates each unit-cell. The nonlinear conversion and the phase-delay mechanism operate collectively to facilitate angle-independent nonreciprocity by imposing different phase gradients during up-conversion and down-conversion processes, and by preventing generation of certain propagative harmonics due to total internal reflection.

A transmit-array collimating assembly, this collimating assembly being able to convert a first electromagnetic wave radiated from a first focal point and in a first frequency band, into a plane electromagnetic wave of same frequency radiated in a preset first direction, and to convert a second electromagnetic wave radiated from a second focal point and in a second frequency band, into a plane electromagnetic wave of same frequency radiated in the same preset first direction, first and second primary radiating elements solely connected to first and second output ports of a transmitting module, respectively. The first and second primary radiating elements are positioned so as to radiate the first and second electromagnetic waves from the first and second focal points, respectively.

A transmit-array collimating assembly, this collimating assembly being able to convert a first electromagnetic wave radiated from a first focal point and in a first frequency band, into a plane electromagnetic wave of same frequency radiated in a preset first direction, and to convert a second electromagnetic wave radiated from a second focal point and in a second frequency band, into a plane electromagnetic wave of same frequency radiated in the same preset first direction, first and second primary radiating elements solely connected to first and second output ports of a transmitting module, respectively. The first and second primary radiating elements are positioned so as to radiate the first and second electromagnetic waves from the first and second focal points, respectively.

Methods, apparatus and systems for radio-based voice activity detection are described. In one example, a described system comprises: a transmitter configured to transmit a radio signal through a wireless channel of a venue; a receiver configured to receive the radio signal through the wireless channel, wherein the wireless channel is impacted by a voice activity of a target voice source in the venue; and a processor. The processor is configured for: computing a time series of channel information (CI) of the wireless channel based on the radio signal, and detecting the voice activity of the target voice source based on the time series of CI (TSCI) of the wireless channel, without using any media signal.

Methods, apparatus and systems for radio-based voice activity detection are described. In one example, a described system comprises: a transmitter configured to transmit a radio signal through a wireless channel of a venue; a receiver configured to receive the radio signal through the wireless channel, wherein the wireless channel is impacted by a voice activity of a target voice source in the venue; and a processor. The processor is configured for: computing a time series of channel information (CI) of the wireless channel based on the radio signal, and detecting the voice activity of the target voice source based on the time series of CI (TSCI) of the wireless channel, without using any media signal.

Apparatus and methods for antenna arrays with staggered rows of antennas for dual frequency operation are provided. In certain embodiments, a mobile device includes a front-end system including a plurality of radio frequency signal conditioning circuits, an antenna array that includes a plurality of antenna elements including a first row of antenna elements and a second row of antenna elements that are staggered, a plurality of switches coupled between the plurality of radio frequency signal conditioning circuits and the antenna array, and a control circuit configured to control a selection of the plurality of antenna elements by the plurality of switches.

Apparatus and methods for antenna arrays with staggered rows of antennas for dual frequency operation are provided. In certain embodiments, a mobile device includes a front-end system including a plurality of radio frequency signal conditioning circuits, an antenna array that includes a plurality of antenna elements including a first row of antenna elements and a second row of antenna elements that are staggered, a plurality of switches coupled between the plurality of radio frequency signal conditioning circuits and the antenna array, and a control circuit configured to control a selection of the plurality of antenna elements by the plurality of switches.

Antennas oriented at a first orientation toward an area of interest can transform radar signals through a first transformation that physically maps the plurality of radar signals with a plurality of unique beam angles corresponding to a plurality of unique frequencies. Antennas oriented at a second orientation toward the area of interest can transform radar signals through a second transformation completing the first transformation. A frequency scan can be performed on a first plurality of responses to first radar signals to identify first spatial data along a first dimension. Second spatial data at second spatial location along a second dimension can be created from a second plurality of responses corresponding to the second transformation. An image can be generated using the first spatial data and the second spatial data while a range value of the area of interest can be determined using the first plurality of responses.