Abstract: In some embodiments, an apparatus includes an antenna, analog circuitry, a radio-frequency identification (RFID) state machine, a radio-frequency-to-direct current (RF-to-DC) converter, and one of a splitter or a switch operatively coupled to the RF-to-DC converter and the RFID state machine. The analog circuitry configured to demodulate a first portion of a radio frequency (RF) signal received via the antenna to produce a demodulated RF signal. The RFID state machine configured to decode the first portion of the demodulated RF signal to produce a decoded signal, and to generate an output signal based on the decoded signal. The RF-to-DC converter can be configured to receive a second portion of the RF signal from the antenna and to convert the second portion of the RF signal to a power associated with a direct current (DC) voltage. The RFID state machine and the external assembly each configured to operate based on the power.

Abstract: Aspects of the disclosure relate to methods, apparatus, and systems for mitigating signal attenuation at a body-worn device transmitting a radio signal. An antenna structure for the body-worn device includes an antenna array configured to radiate at least one radio signal and a conductive band capacitively coupled to the antenna array. The conductive band is configured to detachably couple to a body of a user, and mitigate attenuation of the at least one radio signal when the conductive band is coupled to the body. The conductive band mitigates the attenuation by facilitating a radio frequency (RF) signal current corresponding to the at least one radio signal to flow through the conductive band and preventing absorption of the RF signal current by the body.

Abstract: In some embodiments, an apparatus includes an antenna, analog circuitry, a radio-frequency identification (RFID) state machine, a radio-frequency-to-direct current (RF-to-DC) converter, and one of a splitter or a switch operatively coupled to the RF-to-DC converter and the RFID state machine. The analog circuitry configured to demodulate a first portion of a radio frequency (RF) signal received via the antenna to produce a demodulated RF signal. The RFID state machine configured to decode the first portion of the demodulated RF signal to produce a decoded signal, and to generate an output signal based on the decoded signal. The RF-to-DC converter can be configured to receive a second portion of the RF signal from the antenna and to convert the second portion of the RF signal to a power associated with a direct current (DC) voltage. The RFID state machine and the external assembly each configured to operate based on the power.

Abstract: Aspects of the disclosure relate to methods, apparatus, and systems for mitigating signal attenuation at a body-worn device transmitting a radio signal. An antenna structure for the body-worn device includes an antenna array configured to radiate at least one radio signal and a conductive band capacitively coupled to the antenna array. The conductive band is configured to detachably couple to a body of a user, and mitigate attenuation of the at least one radio signal when the conductive band is coupled to the body. The conductive band mitigates the attenuation by facilitating a radio frequency (RF) signal current corresponding to the at least one radio signal to flow through the conductive band and preventing absorption of the RF signal current by the body.

Abstract: In some embodiments, an apparatus includes an antenna; a radio-frequency (RF) tuning network configured to receive an input signal via the antenna; an RF energy harvester operatively coupled to the RF tuning network and configured to produce a direct current (DC) output based on the received output of the RF tuning network; and a load manipulator configured to be transitioned between a first configuration and a second configuration to manipulate one or more properties associated with the RF energy harvester such that an input impedance of the RF energy harvester changes from a first input impedance to a second input impedance. The first input impedance is associated with a first distribution of RF energy associated with the input signal relative to the RF energy harvester and the second input impedance is associated with a second distribution of RF energy associated with the input signal relative to the RF energy harvester.

Abstract: In some embodiments, an apparatus includes an antenna and a rectifier operatively coupled to the antenna and configured to receive an input power via the antenna. The rectifier can include a plurality of stages, each stage of the plurality of stages including a tuning network including one or more lumped elements. An initial stage can be configured to receive the input power and produce a power based on the input power. Each stage of the plurality of stages coupled to the antenna via at least one previous stage can be configured to receive a power from the previous stage and to produce a subsequent power associated with (e.g., based on) the power received from the previous stage. The rectifier can be configured to output a power associated with a direct current (DC) voltage having a voltage level based on a voltage level associated with the input power.

Abstract: Aspects of the disclosure relate to methods, apparatus, and systems for mitigating signal attenuation at a body-worn device transmitting a radio signal. An antenna structure for the body-worn device includes an antenna array configured to radiate at least one radio signal and a conductive band capacitively coupled to the antenna array. The conductive band is configured to detachably couple to a body of a user, and mitigate attenuation of the at least one radio signal when the conductive band is coupled to the body. The conductive band mitigates the attenuation by facilitating a radio frequency (RF) signal current corresponding to the at least one radio signal to flow through the conductive band and preventing absorption of the RF signal current by the body.