Apparatus for recognizing security code having electromagnetic band-gap pattern

• US 8,146,800 B2
• Filed: 06/04/2010
• Issued: 04/03/2012
• Est. Priority Date: 06/11/2009
• Status: Active Grant

• Current Assignee: Korea Minting, Security Printing & ID Card Operating Corp.
• Original Assignee: Korea Minting, Security Printing & ID Card Operating Corp.
• Inventors: Yu, Jong Won, Jang, Hyeong Seok, Lim, Won Gyu, Jeong, Won Seok, Ryu, Jin Ho, Kim, Hyun Mi
• Primary Examiner(s): Labaze, Edwyn
• Application Number:
  US12/794,699
• Publication Number:
  US 20110108617A1
• Time in Patent Office: 669 Days
• Field of Search: 235/375, 235/449, 235/493, 235/487, 235/488, 235/380, 235/492, 343/787
• US Class Current: 235/375
• CPC Class Codes: G06K 19/0672 with resonating marks
• CPC Class Codes: G06K 7/10009 sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
• CPC Class Codes: H01P 1/2005 Electromagnetic photonic bandgaps [EPB], or photonic bandgaps [PBG]

Abstract

In an apparatus for recognizing a security code having an electromagnetic band gap (EBG) pattern which uses reflection and transmission characteristics of the EBG pattern, a voltage controlled oscillator generates a signal to a power divider, which divides the power of the signal into halves, and outputs a first signal through a waveguide to be incident on the EBG pattern. The waveguide receives a signal reflected from the EBG pattern and outputs the reflected signal to a phase detector. A circulator outputs the second signal to the phase detector, which detects the phase difference between the reflected signal and the second signal, and outputs phase difference data to a data control unit, which determines whether the security code having the EBG pattern is recognized using the phase difference data. In an alternate embodiment, the voltage control oscillator is controlled to sequentially generate signals using power difference data.

Claims

1. An apparatus for detecting and recognizing a security code of a security product having an Electromagnetic Band-Gap (EBG) pattern arranged on the security product, the EBG being configured to resonate at a specific frequency, the apparatus comprising:

a voltage controlled oscillator configured to sequentially generate one or more incident signals having various frequencies;

a power divider configured to divide power of each of the one or more incident signals generated by the voltage controlled oscillator into halves, and to output a first incident signal and a second incident signal;

a waveguide configured to enable the first incident signal to be incident on the EBG pattern, and to receive a reflected signal from the EBG pattern;

a phase detector configured to detect a phase difference between the reflected signal received from the waveguide and the second incident signal received from the power divider, and to generate and output phase data the detected phase difference; and

a data control unit configured to determine whether the security code having the EBG pattern is recognized by using the phase data received from the phase detector, and to control the voltage controlled oscillator to sequentially generate the incident signal.

2. The apparatus as set forth in claim 1, further comprising a power amplifier configured to amplify the power of the incident signal generated by the voltage controlled oscillator, and to output a resulting signal to the power divider.

3. The apparatus as set forth in claim 1, further comprising a circulator configured to transmit the first incident signal received from the power divider to the waveguide, and to transmit the reflected signal received from the waveguide to the phase detector.

4. The apparatus as set forth in claim 1, wherein the security product, on which the EBG pattern is formed, has Perfect Magnetic Conductor (PMC) reflection characteristics in which a phase difference between an incident wave and a reflected wave is 0°

when resonance occurs, and has Perfect Electric Conductor (PEC) reflection characteristics in which the phase difference between the incident wave and the reflected wave is 180°

when resonance does not occur.

5. The apparatus as set forth in claim 1, wherein the phase detector is configured to output an electrical signal having a voltage level which changes depending on the detected phase difference between the reflected signal and the second incident signal.

6. The apparatus as set forth in claim 5, wherein the data control unit comprises:

an analog-to-digital converter configured to convert the electrical signal received from the phase detector into a digital signal;

a micro controller unit configured to determine whether the digital signal obtained by the conversion of the analog-to-digital converter is identical with a preset digital signal, and to output a control signal which enables the voltage controlled oscillator to generate a subsequent incident signal depending on a result of the determination; and

a digital-to-analog converter configured to convert the control signal received from the micro controller unit into an electrical signal, and to output the electrical signal to the voltage controlled oscillator.

7. An apparatus for detecting and recognizing a security code of a security product having an Electromagnetic Band Gap (EBG) pattern arranged on the security product, the EBG being configured to resonate at a specific frequency, the apparatus comprising:

a voltage controlled oscillator configured to sequentially generate one or more incident signals having various frequencies;

a waveguide unit configured to enable each of the one or more incident signals generated by the voltage controlled oscillator to be incident on the EBG pattern, and to receive a transmitted signal passed through the EBG pattern;

a power detector configured to calculate a power difference between the transmitted signal received from the waveguide unit and the one or more incident signals, to compare sizes of the calculated power difference and a reference power difference, and to generate and output power data based on results of the comparison; and

a data control unit configured to determine whether the security code having the EBG pattern is recognized by using the power data received from the power detector, and to control the voltage controlled oscillator to sequentially generate the one or more incident signals.

8. The apparatus as set forth in claim 7, further comprising a power amplifier configured to amplify power of the one or more incident signals generated by the voltage controlled oscillator, and to output a resulting signal to the waveguide unit.

9. The apparatus as set forth in claim 7, wherein the waveguide unit comprises:

a first waveguide configured to enable the one or more incident signals generated by the voltage controlled oscillator to be incident on the EBG pattern; and

a second waveguide configured to receive the transmitted signal passed through the EBG pattern.

10. The apparatus as set forth in claim 7, wherein the power detector is configured to output an electrical signal having a voltage level which changes depending on the result of the comparison of the sizes between the calculated power difference and the reference power difference.

11. The apparatus as set forth in claim 10, wherein the data control unit comprises:

an analog-to-digital converter configured to convert the electrical signal received from the power detector into a digital signal;

a micro controller unit configured to determine whether the digital signal obtained by the conversion of the analog-to-digital converter is identical with a preset digital signal, and to output a control signal which enables the voltage controlled oscillator to generate a subsequent incident signal depending on a result of the determination; and

a digital-to-analog converter configured to convert the control signal from the micro controller unit into an electrical signal, and to output the electrical signal to the voltage controlled oscillator.

12. An apparatus for detecting and recognizing a security code of a security product having an Electromagnetic Band Gap (EBG) pattern arranged on the security product, the EBG being configured to resonate at a specific frequency, the apparatus comprising:

a voltage controlled oscillator configured to sequentially generate one or more incident signals having various frequencies;

a power divider configured to divide power of each of the one or more incident signals generated by the voltage controlled oscillator into halves, and to output a first incident signal and a second incident signal;

a waveguide configured to enable the first incident signal to be incident on the EBG pattern, and to receive a reflected signal from the EBG pattern;

a phase detector configured to detect a phase difference between the reflected signal received from the waveguide and the second incident signal received from the power divider, and to generate and output phase data based on the detected phase difference;

a data control unit configured to determine whether the security code having the EBG pattern is recognized by using the phase data received from the phase detector, and to control the voltage controlled oscillator to sequentially generate the incident signal;

a power amplifier configured to amplify the power of the incident signal generated by the voltage controlled oscillator, and to output a resulting signal to the power divider; and

a circulator configured to transmit the first incident signal received from the power divider to the waveguide, and to transmit the reflected signal received from the waveguide to the phase detector;

wherein the security product, on which the EBG pattern is formed, has Perfect Magnetic Conductor (PMC) reflection characteristics in which a phase difference between an incident wave and a reflected wave is 0°

when resonance occurs, and has Perfect Electric Conductor (PEC) reflection characteristics in which the phase difference between the incident wave and the reflected wave is 180°

when resonance does not occur,

wherein the phase detector is configured to output an electrical signal having a voltage level which changes depending on the detected phase difference between the reflected signal and the second incident signal, and

wherein the data control unit comprises;

an analog-to-digital converter configured to convert the electrical signal received from the phase detector into a digital signal;

a micro controller unit configured to determine whether the digital signal obtained by the conversion of the analog-to-digital converter is identical with a preset digital signal, and to output a control signal which enables the voltage controlled oscillator to generate a subsequent incident signal depending on a result of the determination; and

a digital-to-analog converter configured to convert the control signal received from the micro controller unit into an electrical signal, and to output the electrical signal to the voltage controlled oscillator.

13. An apparatus for detecting and recognizing a security code of a security product having an Electromagnetic Band Gap (EBG) pattern arranged on the security product, the EBG being configured to resonate at a specific frequency, the apparatus comprising:

a voltage controlled oscillator configured to sequentially generate one or more incident signals having various frequencies;

a waveguide unit configured to enable each of the one or more incident signals generated by the voltage controlled oscillator to be incident on the EBG pattern, and to receive a transmitted signal passed through the EBG pattern;

a power detector configured to calculate a power difference between the transmitted signal received from the waveguide unit and the one or more incident signals, to compare sizes of the calculated power difference and a reference power difference, and to generate and output power data based on results of the comparison;

a data control unit configured to determine whether the security code having the EBG pattern is recognized by using the power data received from the power detector, and to control the voltage controlled oscillator to sequentially generate the one or more incident signals; and

a power amplifier configured to amplify power of the one or more incident signals generated by the voltage controlled oscillator, and to output a resulting signal to the waveguide unit;

wherein the waveguide unit comprises;

a first waveguide configured to enable the one or more incident signals generated by the voltage controlled oscillator to be incident on the EBG pattern; and

a second waveguide configured to receive the transmitted signal passed through the EBG pattern,

wherein the power detector is configured to output an electrical signal having a voltage level which changes depending on the result of the comparison of the sizes between the calculated power difference and the reference power difference, and

wherein the data control unit comprises;

an analog-to-digital converter configured to convert the electrical signal received from the power detector into a digital signal;

a micro controller unit configured to determine whether the digital signal obtained by the conversion of the analog-to-digital converter is identical with a preset digital signal, and to output a control signal which enables the voltage controlled oscillator to generate a subsequent incident signal depending on a result of the determination; and

a digital-to-analog converter configured to convert the control signal received from the micro controller unit into an electrical signal, and output the electrical signal to the voltage controlled oscillator.