METHOD FOR REMOTE MEASURING OF A PHYSICAL VARIABLE

• US 20110043334A1
• Filed: 08/22/2008
• Published: 02/24/2011
• Est. Priority Date: 08/24/2007
• Status: Active Grant

• Current Assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
• Original Assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
• Inventors: Theeuwes, Johannes Adrianus Cornelis
• Granted Patent: US 8,493,184 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: H04Q 2209/40 using a wireless architecture
• CPC Class Codes: H04Q 2209/84 Measuring functions
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

System for remote measuring a physical variable comprising an RF transceiver arranged for transmitting an RF signal and for receiving a reflection signal derived from the transmitted signal. An RF transponder comprises a dielectric material having a dielectric property which is dependent on the physical variable according to a first function. The dielectric material is exposed to the physical variable to be measured. The transponder is arranged to receive the signal transmitted by the transceiver and to reflect a reflection signal, or the second and/or higher harmonics of it, which is dependent on the actual dielectric property. Processing means are provided for comparing the signal transmitted by the transceiver and the reflection signal received from the transponder and for converting the comparison result, e.g. the phase shift, into a value which is representative for the physical variable to be measured. The transponder may be e.g. a patch antenna.

Claims

1. Method for remote measuring a physical variable comprising next steps:

providing an RF transceiver arranged for transmitting an RF signal and for receiving a reflection signal which is derived from said transmitted signal;

providing an RF transponder comprising a dielectric material having a dielectric property which is dependent on said physical variable according to a first function and which dielectric material is exposed to said physical variable v to be measured;

the transponder being arranged to receive the signal transmitted by the transceiver and to reflect, as said reflection signal, a signal which is dependent on the signal transmitted by the transceiver and of the actual dielectric property according to a second function;

providing processing means for comparing the signal transmitted by the transceiver and the reflection signal received from the transponder and for converting the comparison result into a value which is representative for the physical variable to be measured, applying said first function and second function.

2. Method according to claim 1, wherein the attenuation is measured of the reflection signal compared with the signal transmitted by the transceiver.

3. Method according to claim 1, wherein the phase shift is measured of the reflection signal compared with the signal transmitted by the transceiver.

4. Method according to any preceding claim, wherein the transponder converts the signal received from the transceiver into second and/or higher harmonics and reflects said reflection signal comprising said harmonics;

wherein, moreover, in said transceiver the harmonics are discriminated from the fundamental frequency of the signal transmitted by the transceiver.

5. System for remote measuring a physical variable comprising an RF transceiver arranged for transmitting an RF signal and for receiving a reflection signal which is derived from said transmitted signal;

an RF transponder comprising a dielectric material having an dielectric property which is dependent on said physical variable according to a first function and which dielectric material, in operation, is exposed to said physical variable to be measured;

the transponder being arranged to receive the signal transmitted by the transceiver and to reflect, as said reflection signal, a signal which is dependent on the signal transmitted by the transceiver and of the actual dielectric property according to a second function;

processing means for comparing the signal transmitted by the transceiver and the reflection signal received from the transponder and for converting the comparison result into a value which is representative for the physical variable to be measured, applying said first function and second function.

6. System according to claim 5, the processing means being arranged to measure the phase shift of the reflection signal compared with the signal transmitted by the transceiver.

7. System according to claim 5 or 6, wherein the transponder comprises means for converting the signal received from the transceiver into second and/or higher harmonics of that signal and for reflecting at least part of those harmonics;

wherein, moreover, said transceiver comprises means for discriminating the harmonics from the fundamental frequency of the signal transmitted by the transceiver.

8. System according to claim 7, the transponder comprising at least two reflecting antenna electrodes interconnected via an interconnection circuit comprising a diode.

9. System according to claim 5, the transponder comprising at least two reflecting antenna electrodes, having the shape of a micro strip antenna, a printed antenna, a micro strip patch antenna or a patch antenna.