Co-planar, near field communication telemetry link for an analyte sensor

Abstract

An inductive sensor system for remote powering and communication with an analyte sensor (e.g., a fully implantable analyte sensor). The system may include an analyte sensor and transceiver. The system may be ferrite-enhanced. The transceiver may implement a passive telemetry for communicating with the analyte sensor via an inductive magnetic link for both power and data transfer. The link may be a co-planar, near field communication telemetry link. The transceiver may include a reflection plate configured to focus flux lines linking the transceiver and the sensor uniformly beneath the transceiver. The transceiver may include an amplifier configured to amplify battery power and provide radio frequency (RF) power to a transceiver antenna.

What is claimed is: 
     
         1 . A transceiver for interfacing with an analyte sensor, the transceiver comprising:
 an interface device configured to convey a power signal to the analyte sensor and to receive data signals from the analyte sensor; and   a reflection plate configured to focus flux lines linking the interface device and the analyte sensor uniformly beneath the transceiver.   
     
     
         2 . The transceiver of  claim 1 , wherein the reflection plate is rigid. 
     
     
         3 . The transceiver of  claim 1 , wherein the reflection plate is flexible. 
     
     
         4 . The transceiver of  claim 1 , wherein the reflection plate is metal. 
     
     
         5 . The transceiver of  claim 4 , wherein the reflection plate is aluminum. 
     
     
         6 . The transceiver of  claim 1 , wherein the interface device is an antenna. 
     
     
         7 . The transceiver of  claim 6 , wherein the antenna has a ferrite core. 
     
     
         8 . The transceiver of  claim 7 , wherein the ferrite core has a high quality factor and a high permeability. 
     
     
         9 . The transceiver of  claim 7 , wherein the ferrite core is an NiZn based ferrite material. 
     
     
         10 . The transceiver of  claim 6 , wherein the antenna is a flat antenna. 
     
     
         11 . The transceiver of  claim 1 , wherein the reflection plate increases the efficiency of the interface device. 
     
     
         12 . The transceiver of  claim 1 , wherein the reflection plate covers at least a portion of the interface device. 
     
     
         13 . The transceiver of  claim 1 , wherein the interface device is attached to the reflection plate. 
     
     
         14 . The transceiver of  claim 2 , wherein the reflection plate provides mechanical support for the interface device. 
     
     
         15 . The transceiver of  claim 1 , further comprising a printed circuit board (PCB) assembly, wherein the reflection plate protects the interface device from random detuning caused by the PCB assembly. 
     
     
         16 . A transceiver for interfacing with an analyte sensor, the transceiver comprising:
 an antenna configured to convey a power signal to the analyte sensor and to receive data signals from the analyte sensor;   a battery configured to provide battery power;   an amplifier configured to amplify the battery power and provide radio frequency (RF) power to the antenna, wherein the provided RF power is sufficient to power the analyte sensor at a required range.   
     
     
         17 . The transceiver of  claim 16 , wherein the amplifier is a Class E amplifier. 
     
     
         18 . The transceiver of  claim 16 , wherein the required range is greater than or equal to 0.5 inches. 
     
     
         19 . The transceiver of  claim 16 , wherein the required range is greater than or equal to one inch. 
     
     
         20 . The transceiver of  claim 16 , wherein the battery is a lithium-polymer battery. 
     
     
         21 . The transceiver of  claim 16 , wherein the antenna has a ferrite core. 
     
     
         22 . The transceiver of  claim 21 , wherein the ferrite core has a high quality factor and a high permeability. 
     
     
         23 . The transceiver of  claim 21 , wherein the ferrite core is an NiZn based ferrite material. 
     
     
         24 . The transceiver of  claim 16 , wherein the antenna is a flat antenna. 
     
     
         25 . The transceiver of  claim 16 , further comprising a housing, wherein the antenna is contained within the housing. 
     
     
         26 . The transceiver of  claim 16 , further comprising an antenna fault detection circuit configured to provide an indication that the antenna failed to convey the power signal to the analyte sensor. 
     
     
         27 . The transceiver of  claim 16 , further comprising a shutdown safety circuit configured to shut down the amplifier if the amplifier provides the RF power to the antenna for a predetermined amount of time. 
     
     
         28 . The transceiver of  claim 16 , further comprising a pi filter configured to high harmonics. 
     
     
         29 . The transceiver of  claim 16 , further comprising an antenna matching circuit configured to provide good matching between an output impedance of the amplifier and an input impedance of the antenna. 
     
     
         30 . The transceiver of  claim 16 , further comprising an radio-frequency identification (RFID) integrated circuit (IC) configured to encode data to be conveyed to the analyte sensor and to decode data received from the analyte sensor. 
     
     
         31 . The transceiver of  claim 30 , further comprising an amplifier drive sub-circuit configured to match an input impedance of the amplifier and an output impedance of the RFID IC. 
     
     
         32 . The transceiver of  claim 16 , wherein the amplifier feeds directly from the battery and does rely on an intermediate boost converter. 
     
     
         33 . A transceiver for interfacing with an analyte sensor, the transceiver comprising:
 an antenna configured to convey a power signal to the analyte sensor and to receive data signals from the analyte sensor;   an antenna fault detection circuit configured to output a voltage proportional to a field strength of the antenna; and   a microcontroller configured to measure the voltage output by the antenna fault detection circuit and determine whether the antenna is emitting a strong enough signal.   
     
     
         34 . The transceiver of  claim 33 , wherein antenna fault detection circuit comprises an unshielded inductor configured to act as a receiving antenna. 
     
     
         35 . The transceiver of  claim 34 , wherein the unshielded inductor has a ferrite core. 
     
     
         36 . The transceiver of  claim 34 , wherein antenna fault detection circuit further comprises a capacitor and a diode, wherein the inductor, capacitor, and diode form a resonant circuit.