Massachusetts Institute of Technology

Qualcomm Incorporated

The Brigham and Women's Hospital, Inc.

Cornell University

Yunfei Ma

Fadel Adib

Nicholas Selby

Jonghae Kim

Changhan Hobie Yun

Mario Francisco Velez

Daeik Daniel Kim

Chengjie Zuo

David Francis Berdy

Niranjan Sunil Mudakatte

Robert Paul Mikulka

Zhihong Luo

Je-Hsiung Lan

Carlo Giovanni Traverso

Unsoo Ha

Junshan Leng

Zexuan Zhong

Christoph Steiger

Qiping Zhang

Manish Singh

Alaa Khaddaj

Tzu Ming Hsu

Edwin C Khan

A transceiver may wirelessly transmit a communication signal at a first frequency and a sensing signal at a second frequency. The communication signal may include a command that causes a backscatter node to modulate impedance of an antenna, and thereby modulate reflectivity of the backscatter node. The communication signal may also deliver wireless power to the backscatter node. While the impedance is being modulated in response to the command, the transceiver may transmit the sensing signal and measure wireless reflections. The power of the sensing signal may be much lower than that of the communication signal. The transceiver may frequency hop the sensing signal in a wide band of frequencies and take measurements at each frequency in the hopping. Based on the measurements, a computer may determine time-of-flight or phase of a reflected signal from the backscatter node and may estimate location of the backscatter node with sub-centimeter precision.

Methods and apparatus for wideband localization

A system may sense the contents of a closed container, by analyzing a wireless signal that reflects from an RFID tag on the outside of the container. The frequency response of the tag's antenna may be affected by the relative permittivity of the contents and by the tag's environment. The frequency response may be measured in a line-of-sight environment and in a multipath environment. Channel estimates may be calculated, based on the measurements. Channel ratios may be calculated by dividing line-of-sight channel estimates by multipath channel estimates. The resulting channel ratios may be fed into a variational autoencoder, which in turn generates synthetic data that contains information about multipath environments but not the contents. The output of the variational autoencoder may be converted into synthetic channel estimates, which may in turn be employed for anomaly detection, or to train a classifier to classify contents of the container.

Methods and apparatus for radio frequency sensing in diverse environments

Multiple antennas of a beamformer may simultaneously transmit wireless signals at different frequencies. The signals may comprise synchronized, identical wireless commands, each at a different carrier frequency. The transmitted signals may constructively and destructively interfere with each other at a receiver antenna, to form a beat signal. When the transmitted signals constructively interfere, the beat signal may cause a voltage in the receiver to exceed a threshold voltage. The threshold voltage may be a minimum voltage at which a device, which is operatively connected to the receiver antenna, is able to perform energy harvesting or wireless communication. The beamformer may operate under blind channel conditions, because the transmitted frequencies may be selected in such a way as to maximize peak power delivered under all possible channel conditions. The beamformer may deliver wireless power to a sensor or actuator that is located deep inside bodily tissue.

Methods and apparatus for multi-frequency beamforming

A wideband, radio-frequency localization system may estimate the one-dimensional, two-dimensional or three-dimensional position and trajectory of a static or moving object. These estimates may have a high spatial accuracy and low latency. The localization may be determined based on phase or amplitude of a wideband signal in each frequency band in a set of multiple frequency bands. The localization may be based on a single shot of measurements across a wide band of radio frequencies, without frequency hopping. The measurements of the wideband signal may be taken over time and over space at multiple receivers. The localization may be based on measurements taken while a backscatter node remains in a first reflective state or in a second reflective state, rather than when the backscatter node is transitioning between reflective states. In some cases, the localization achieves sub-centimeter spatial resolution in each of three spatial dimensions.

A method may comprise relaying a wireless signal via a bi-directional, full-duplex relay. The relay may comprise an analog uplink relay and an analog downlink relay, and may relay signals between a transmitter and a backscatter node. The spectrum of the downlink signal transmitted by the downlink relay may be different than the spectrum of the uplink signal received by the uplink relay. Filtering may attenuate leakage from the downlink relay to the uplink relay, and vice versa. The uplink relay may create a phase offset that is opposite in sign and substantially equal in magnitude to the phase offset created by the downlink relay. The downlink and uplink relays, taken together, may create a substantially constant net phase offset. The full-duplex relay may be housed in a vehicle that moves, and may be used to determine spatial coordinates of backscatter sources that are located in the relay's environment.

Method for relaying signals via a full-duplex, bi-directional relay

Disclosed is an apparatus including a plurality of vias each having a defined shape, wherein each of the plurality of vias includes a first two-dimensional conductive layer plated on a first side of a substrate, the first two-dimensional conductive layer having the defined shape, a second two-dimensional conductive layer plated on a second side of the substrate, the second two-dimensional conductive layer having the defined shape, and a via conductively coupling the first two-dimensional conductive layer to the second two-dimensional conductive layer. The apparatus further includes a plurality of interconnects configured to conductively couple the plurality of vias, wherein the first two-dimensional conductive layer and the second two-dimensional conductive layer of each of the plurality of vias are perpendicular to the plurality of interconnects.

Two-dimensional structure to form an embedded three-dimensional structure

A full-duplex analog relay may comprise an analog uplink relay and an analog downlink relay, and may relay signals between a transmitter and a backscatter node. The spectrum of the downlink signal transmitted by the downlink relay may be different than the spectrum of the uplink signal received by the uplink relay. Filtering may attenuate leakage from the downlink relay to the uplink relay, and vice versa. The uplink relay may create a phase offset that is opposite in sign and substantially equal in magnitude to the phase offset created by the downlink relay. The downlink and uplink relays, taken together, may created a substantially constant net phase offset. The full-duplex relay may be housed in a vehicle that moves, and may be used to determine spatial coordinates of backscatter sources that are located in the relay's environment.

Full-duplex, bi-directional, analog relay

An inductor with multiple loops and semiconductor devices with such an inductor integrated thereon are proposed. In an aspect, the semiconductor device may include a die on a substrate, an inductor on the die in which the inductor comprises a wire with multiple non-planar loops above the die. In another aspect, the semiconductor device may include a plurality of posts on a die on a substrate, and an inductor on the die. The inductor may include a wire looped around the plurality of posts such that the inductor includes multiple non-planar loops.

Solenoid inductor

A tunable matching network is disclosed. In a particular example, the matching network includes at least one first inductor in a signal path of the matching network. The matching network includes at least one second inductor outside of the signal path. The matching network includes one or more switches coupled to the at least one second inductor. The one or more switches are configured to selectively enable mutual coupling of the at least one first inductor and the at least one second inductor.

Tunable matching network

An RF diplexer is provided that includes a first channel and a second channel. The first channel includes a first primary inductor. Similarly, the second channel includes a second primary inductor. A first directional coupler for the first channel includes a first transformer formed by the first primary inductor and also a first secondary inductor. A first terminal for the first secondary inductor is a coupled port for the first directional coupler. A second directional coupler for the second channel includes a second transformer formed by the second primary inductor and also a second secondary inductor. A first terminal for the second secondary inductor is a coupled port for the second directional coupler.

RF multiplexer with integrated directional couplers

A device includes an acoustic resonator embedded within an encapsulating structure that at least partially encapsulates the acoustic resonator. The device includes an inductor electrically connected to the acoustic resonator. At least a portion of the inductor is embedded in the encapsulating structure.

Growing community of inventors

Santa Clara, CA, United States of America

Yunfei Ma