Slot antenna system for ingestible devices
Introduced here is a digital pill comprised of a capsule, an ingestible sensor, and a slot antenna. The ingestible sensor can be configured to generate a signal indicative of a characteristic of the living body in which the digital pill is located. Biometric data can be stored, at least temporarily, in a memory in the form of signal values. For example, the slot antenna may transmit biometric data to a computing device across a network on a periodic basis (e.g., every 5 minutes, 15 minutes, 60 minutes, etc.). Alternatively, the slot antenna may stream biometric data to a computing device across the network in real time.
1. A device designed for ingestion by a living body, the device comprising:
a spherocylinder capsule formed from a molded substrate that includes
an insulating layer with an inner surface that defines a cavity, and
a metal layer disposed along an outer surface of the insulating layer,
wherein the spherocylinder capsule includes a cylindrical body having hemispherical ends,
wherein the metal layer has a slot defined therethrough that extends circumferentially along one of the hemispherical ends and then longitudinally along opposing sides of the cylindrical body, so as to have a U-shaped form, and
wherein a portion of the insulating layer is exposed to an in vivo environment through the slot in the metal layer;
a sensor configured to generate signal values indicative of a biological feature; and
a processor configured to:
store biometric data representative of the signal values in a memory; and
cause transmission of at least some of the biometric data to a computing device external to the living body by applying a driving current to the metal layer,
wherein said application of the driving current causes the slot to radiate electromagnetic waves, thereby operating as a slot antenna.
2. The device of claim 1 , further comprising:
a first conductive element disposed along the inner surface of the insulating layer.
3. The device of claim 2 , wherein the processor is mounted to a circuit board secured within the cavity, and wherein the first conductive element is electrically connected to the circuit board.
4. The device of claim 2 , wherein the first conductive element extends along the inner surface of the insulating layer substantially parallel to the slot defined through the metal layer.
5. The device of claim 2 , further comprising:
a second conductive element configured to ground the slot antenna to an outer surface of the metal layer.
6. The device of claim 1 , further comprising:
a power component configured to generate the driving current,
wherein the power component is secured within the cavity.
7. The device of claim 6 , further comprising:
a power via implemented through a circuit board on which the processor is mounted,
wherein a first end of the power via is connected to the power component, and
wherein a second end of the power via is connected to a supply voltage terminal of circuitry printed on the circuit board to provide power.
8. The device of claim 6 , wherein the power component is a silver-oxide button cell battery.
9. The device of claim 1 , wherein the insulating layer is comprised of alumina or another ceramic material.
10. A device designed for ingestion by a living body, the device comprising:
a metal capsule having a slot defined therethrough, such that an insulating layer disposed along an inner surface of the metal capsule is partially exposed to an in vivo environment;
a sensor configured to generate signal values indicative of a biological feature;
a power component configured to generate a driving current to be applied to the metal capsule to radiate electromagnetic waves; and
a processor configured to cause transmission of data representative of the signal values to a receiver located outside the living body via the electromagnetic waves.
11. The device of claim 10 , wherein the metal capsule has an elongate shape with a pair of rounded ends.
12. The device of claim 10 , further comprising:
a conductive element disposed along an inner surface of the insulating layer.
13. The device of claim 12 , wherein the conductive element extends along the inner surface of the insulating layer substantially parallel to the slot defined through the metal capsule.
14. The device of claim 10 , wherein the metal capsule includes a cylindrical body having hemispherical ends, and wherein the slot extends circumferentially along a surface of one hemispherical end and longitudinally along opposing sides of the cylindrical body.
15. A method comprising:
receiving input indicative of an instruction to operate a sensor of a device designed for ingestion by a living body;
causing the sensor to generate signal values indicative of a monitored characteristic of the living body; and
forwarding the signal values to a transceiver for modulation onto a metal capsule of the device for transmission to a receiver,
wherein the metal capsule has an elongate body with rounded ends, and
wherein the metal capsule has a slot defined therethrough so that the metal capsule is able to act as a slot antenna when a driving current is applied thereto, the slot extending circumferentially along one of the rounded ends and then longitudinally along opposing sides of the elongate body, so as to have a U-shaped form.
16. The method of claim 15 , further comprising:
storing at least some of the signal values in the form of biometric data in a memory.
17. The method of claim 15 , wherein the monitored characteristic is pH, temperature, pressure, glucose concentration, or medication concentration.
18. The method of claim 15 , wherein said forwarding is performed periodically so that batches of signal values are transmitted to the receiver in the form of electromagnetic waves on a periodic basis.