TRANSPONDER, INTERROGATOR, AND COMMUNICATION DEVICE
First Claim
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1. A transponder comprising:
- an antenna circuit to perform communication with an interrogator, which is a communication subject, via electromagnetic waves,wherein said antenna circuit includes a coil and a variable capacity circuit connected in parallel,and wherein the tuning frequency thereof is a first frequency; and
a tuning frequency control circuit configured to switch the tuning frequency of said coil and variable capacity circuit connected in parallel to a second frequency in the case of transmitting electromagnetic waves with said antenna circuit.
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Abstract
A transponder is provided which includes an antenna circuit to perform communication with an interrogator, which is a communication subject, via electromagnetic waves. The antenna circuit includes a coil and a variable capacity circuit mutually connected in parallel, and the tuning frequency thereof is a first frequency. The transponder also includes a tuning frequency control circuit to switch the tuning frequency of the coil and the variable capacity circuit mutually connected in parallel to a second frequency in the case of transmitting electromagnetic waves with the antenna circuit.
48 Citations
18 Claims
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1. A transponder comprising:
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an antenna circuit to perform communication with an interrogator, which is a communication subject, via electromagnetic waves, wherein said antenna circuit includes a coil and a variable capacity circuit connected in parallel, and wherein the tuning frequency thereof is a first frequency; and a tuning frequency control circuit configured to switch the tuning frequency of said coil and variable capacity circuit connected in parallel to a second frequency in the case of transmitting electromagnetic waves with said antenna circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An interrogator comprising:
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an antenna circuit including a coil and a variable capacity circuit connected in parallel to perform communication with a transponder, which is a communication subject, via electromagnetic waves; and a tuning frequency control circuit to switch the tuning frequency of said antenna circuit to a first frequency in the case of transmitting an electromagnetic wave from said antenna circuit, and a second frequency in the case of receiving the electromagnetic waves transmitted with said transponder. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A communication device comprising:
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an antenna circuit made up of a coil and a variable capacity circuit connected in parallel to perform communication with another communication device, which is a communication subject, via electromagnetic waves; and a tuning frequency control circuit to switch the tuning frequency of said antenna circuit to a first frequency upon receiving an electromagnetic wave originating from said other communication device, and a second frequency upon transmitting the electromagnetic waves transmitted with said antenna circuit.
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Specification