Communications: electrical – Continuously variable indicating – With meter reading
Patent
1995-03-30
1998-03-31
Horabik, Michael
Communications: electrical
Continuously variable indicating
With meter reading
34082531, 342 44, 310313R, G01S 1504
Patent
active
057343322
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention concerns a method for individual identification using electronic interrogation, and an identification chip for this purpose.
BACKGROUND OF THE INVENTION
The invention is based upon an identification chip having an inactive code carrier, which typically comprises a so-called SAW (Surface Acoustic Wave)-component. Such SAW-components are well known for individual identification. The SAW-component is coded, so that each chip has its own code, which gives a unique identification of the chip, and the object to which it is fastened. In addition, each chip contains an antenna, and optionally components for impedance matching and physical encapsulation.
The use of such indentification chips is based upon a central unit comprising a transmitter and a receiver, generating a microwave signal, which is transmitted and received by the antenna on the identification chip. The signal is then converted to an acoustic surface wave, which propagates along the SAW-component, and gives reflections, mirroring the code of this component. These reflected signals are then converted to an electronic signal. This signal is transmitted from the chip and is received by the receiver in the central unit, where it is further processed for dermining the individual identification.
The are many different embodiments of these components in respect of code methods, code length, physical geometry, choice of material, etc. Furthermore, it is also known to use so-called BAW (Bulk Acoustic Wave)--components for similar purposes.
A disadvantage with SAW-chips is that they are relatively narrow-banded, so that each kind of chip must be manufactured with a special geometry. This makes it more difficult to provide efficient utilization of ultra-high frequencies above 1 GHz,
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method and a device for individual identification using electronic interrogation of the above mentioned kind which permits a more flexible use of frequencies.
The object of the invention is achieved with an identification chip for use in connection with the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following, a preferred embodiment of the invention will be described with reference to the accompanying drawings, in which:
FIG. 1 is a block diagram of a device for use according to present invention,
FIG. 2a and 2b are frequency diagrams for signals transmitted from the transmitter/receiver unit,
FIG. 3a and 3b are frequency diagrams for reflected, coded signal, and
FIG. 4 is a more detailed drawing of the components which are a part of the device according to present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows an identification chip according to present invention. The identification chip is generally denoted 1, and comprises a code carrier 2, e.g. a SAW-component, a frequency mixer 3, and an antenna 4. Signals from a transmitter (not shown) are received by the antenna 4 and are propagated via the mixer 3, to the code carrier 2. From the code carrier 2 a signal is reflected via the mixer 3 and transmitted by the antenna 4, back to the transmitter/receiver unit (not shown).
FIG. 2a is a frequency diagram illustrating the signal which is transmitted from the transmitter. In this example of an embodiment, an interrogation signal f.sub.1 is transmitted together with a carrier signal f.sub.0. This signal is received by the antenna 4 in the identification chip 1. In the mixer 3, a mixed signal f.sub.2, shown in FIG. 2b, is extracted and taken to the code carrier 2. The signal f.sub.2 preferably has a frequency which is the frequency difference of the signals f.sub.1 and f.sub.0.
FIG. 3a shows the reflected signal f.sub.2, from the code carrier 2. This signal f.sub.2, has superimposed thereon the indiviual code carrier 2. Signal f.sub.2, is then again mixed, so that an identification coded mixing signal denoted f.sub.1, is formed, as shown in FIG. 3b. As a result the transmitted and received signals f.sub.0, f.sub.1
REFERENCES:
patent: 4096477 (1978-06-01), Epstein et al.
patent: 4703327 (1987-10-01), Rossetti et al.
patent: 4734698 (1988-03-01), Nysen et al.
patent: 4737790 (1988-04-01), Skeie et al.
patent: 4746830 (1988-05-01), Holland
Horabik Michael
Micro Design AS
Wilson Jr. William H.
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