RF transmitter device and method for operating the same

• US 8,447,238 B2
• Filed: 07/22/2010
• Issued: 05/21/2013
• Est. Priority Date: 07/24/2009
• Status: Active Grant

• Current Assignee: Stichting Imec Nederland
• Original Assignee: Stichting Imec Nederland
• Inventors: Vullers, Ruud, Visser, Hubregt Jannis
• Primary Examiner(s): TRINH, TAN H
• Application Number:
  US12/841,929
• Publication Number:
  US 20110021160A1
• Time in Patent Office: 1,034 Days
• Field of Search: 455/68, 455/69, 455/522, 455/67.11, 455/552.1, 455/404.2, 455/9, 455/13.4, 455/41.2, 455/41.1, 455/572, 455/573, 455/574, 455/115.1, 455/127.1, 455/177.1, 455/343.5, 455/343.2, 455/456.1, 455/343.1, 455/70, 320/108, 342/357.25, 307/9.1, 307/104, 340/572.1, 340/10.1, 340/5.1, 340/522, 714/22
• US Class Current: 455/68
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H02J 50/001 Energy harvesting or scavenging
• CPC Class Codes: H02J 50/27 characterised by the type of receiving antennas, e.g. rectennas
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A radio frequency (RF) transmitter device arranged for supplying RF energy is disclosed. In one aspect, the RF transmitter device has a reception unit for receiving information on detected living beings. The RF transmitter device is arranged for adapting its transmit power according to the received information. A method for adapting the transmit power of the RF transmitter device while it is supplying energy to a sensor network is also disclosed.

Claims

1. A system comprising:

a radio frequency (RF) transmitter device configured to supply energy by RF transmission within a given transmitter coverage area, to receive information about a detected living being, and to adapt a transmit power of the RF transmission according to the received information; and

a plurality of sensor units, each sensor unit configured to detect living beings within a given sensor coverage area and to communicate with the RF transmitter providing information about an identity of the sensor unit and about a detected living being, the plurality of sensor units configured so that a living beings detection area covers an area overlapping the transmitter coverage area,

wherein the RF transmitter is further configured to lower the transmit power of the RF transmission based on the sensor unit identity when detecting a living being.

2. The system of claim 1, wherein the living beings detection area is divided into a first detection area covered by a first plurality of sensor units and a second detection area covered by a second plurality of sensor units.

3. The system of claim 2, wherein the second detection area is closer to the RF transmitter than the first detection area.

4. The system of claim 2, wherein the RF transmitter is configured to lower the transmit power of the RF transmission to a given first power level within the first detection area when a sensor unit of the first plurality of sensor units detects the presence of a living being, and to transmit with a given second power level within the second detection area.

5. The system of claim 4, wherein the first power level is lower than the second power level.

6. The system of claim 4, wherein the living being is a human, the first power level is a level acceptable for human presence and the second power level is a level not acceptable for human presence.

7. The system of claim 4, wherein the RF transmitter is configured to further lower the second power level within the second detection area when a sensor unit of the second plurality of sensor units detects the presence of a human.

8. The system as of claim 1, wherein any of the sensor units is powered by the RF energy transmitted by the RF transmitter.

9. The system of claim 1, wherein at least one of the sensor units is configured to be powered by RF energy transmitted by the RF transmitter device.

10. The system of claim 1, wherein the RF transmitter is further configured to increase the transmit power of the RF transmission based on no detection of a living being.

11. A system comprising:

two or more radio frequency (RF) transmitter devices, each configured to supply energy by RF transmission within a given transmitter coverage area, to receive information about a detected living being, and to adapt a transmit power of the RF transmission according to the received information; and

each RF transmitter being associated to a plurality of sensor units, each sensor units configured to detect living beings within a given sensor coverage area and to communicate with the RF transmitter providing information about an identity of the sensor unit and about a detected living being, the plurality of sensor units configured so that a living beings detection area covers an area overlapping the associated transmitter coverage area,

wherein the two or more RF transmitter devices are configured to share information between each other about a detected living being and wherein each RF transmitter is further configured to lower the transmit power of the RF transmission based on the sensor unit identity when detecting a living being.

12. The system of claim 11 wherein the living beings detection area in the area overlapping with each RF transmitter is divided into a first detection area covered by a first plurality of sensor units and a second detection area covered by a second plurality of sensor unit

13. The system of claim 12 wherein each RF transmitter is further configured to adapt the transmit power of the RF transmission in the first detection area and/or the second detection area based on the information received from a different RF transmitter.

14. The system of claim 13 wherein a first RF transmitter device increases the transmit power of the RF transmission in the first detection area and the second detection area when receiving information from a second RF transmitter device about a living being positioned outside the transmitter coverage area of the first RF transmitter device.

15. The system of claim 11 wherein the RF transmitters are further configured to share information between each other about their respective transmitter coverage areas.