Passive transponder identification and credit-card type transponder
First Claim
1. A passive transponder identification system for detecting and monitoring the existing of automobiles and other object within a constant detection area comprising a transmitter 100 to radiate two different radio frequency (RF) signals within the area to a transmitting antenna 110, either of the signals being modulated to a fixed low frequency (LF) and an antenna 210 modulated with two different center frequencies;
- wherein an impedance semiconductor circuit part 220 inserted into said modulated antenna combines said two RF signals; and
the identification system further includes a transponder 200 having a tank circuit to contain a resonant frequency equal to sum of two different frequencies to re-radiate a data-tone carrier signal to such combined frequency and a narrow-bandwidth receiver 300 having a receiving antenna 310 to receive and demodulate said carrier signal by excluding the transmitting RF signal and its harmonics to detect LF modulating signal.
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Accused Products
Abstract
A passive transponder identification system and credit card type transponder are disclosed, particularly, the transponder identification system to utilize a transmitting manner of two different RF signals is provided. The present invention directly relates to a passive transponder without any kind of power source. Therefore, the present invention has advantages of having a constant gain value by developing a high-gain dual polarizing antenna for a small credit card type passive transponder to identify at long distance, independently to any direction of the transponder; improving gain values than conventional transponder tag antenna by 6-9 dB to ensure a sub-permanent life time by providing the desired identification performance by a small credit card type passive transponder without power supply; and being applicable to any systems to identify and distinguish high-speed moving objects.
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Citations
14 Claims
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1. A passive transponder identification system for detecting and monitoring the existing of automobiles and other object within a constant detection area comprising a transmitter 100 to radiate two different radio frequency (RF) signals within the area to a transmitting antenna 110, either of the signals being modulated to a fixed low frequency (LF) and an antenna 210 modulated with two different center frequencies;
- wherein an impedance semiconductor circuit part 220 inserted into said modulated antenna combines said two RF signals; and
the identification system further includes a transponder 200 having a tank circuit to contain a resonant frequency equal to sum of two different frequencies to re-radiate a data-tone carrier signal to such combined frequency and a narrow-bandwidth receiver 300 having a receiving antenna 310 to receive and demodulate said carrier signal by excluding the transmitting RF signal and its harmonics to detect LF modulating signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- wherein an impedance semiconductor circuit part 220 inserted into said modulated antenna combines said two RF signals; and
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11. A system to detect cars or other objects existing within the detection area comprising a transmitter 100 to run and radiate radio frequencies (RFs) having a narrow-bandwidth by using a carrier frequency modulated by a certain LF tone;
- wherein the system includes a transponder 200 to respond the signal from the transmitter 100 to be radiated by the transmitter 100 to run and re-radiate the carrier signal by different harmonics;
the re-radiated signal comprising a fixed LF tone produced by adding a data stream to the LF tone;
the system further comprises a receiving system 300 having a narrow-bandwidth filter 311 to contain the carrier signal re-radiated at said harmonics so that it produces filtered output corresponding the re-radiation signal received by an antenna 310 to receive said re-radiated carrier signal and to prevent the signals including ones of even the frequencies other than the narrow-bandwidth received by the antenna 310; and
having a demodulation means responding to the comparison level of the output to generate LF modulation signal and demodulate the filtered output even when the comparator 312 exceeds the preset threshold value and runs. - View Dependent Claims (12, 13, 14)
- wherein the system includes a transponder 200 to respond the signal from the transmitter 100 to be radiated by the transmitter 100 to run and re-radiate the carrier signal by different harmonics;
Specification