Antenna device and radio communication apparatus using the antenna device
First Claim
1. An antenna device, comprising:
- a variable reactance circuit having a reactance value variable on the basis of a control signal;
an RF circuit having a matching circuit at an output side;
an antenna element having one end to which an electrical signal is fed from the RF circuit and the other end terminated by the variable reactance circuit; and
a reactance and matching control circuit that outputs the control signal for setting the reactance value of the variable reactance circuit to a predetermined value.
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Accused Products
Abstract
An electrical signal is fed from one terminal of an antenna element, and the other terminal thereof is terminated by a variable reactance circuit. A reactance value of the variable reactance circuit is changed according to use state of a device to optimally set its directivity. Matching conditions at an electricity feeding point are controlled to match an impedance of the electricity feeding point which fluctuates according to the value of the variable reactance circuit. With the above construction, there are provided an antenna device that is downsized, can control its directivity, and does not deteriorate a communication quality depending on a use state, and a radio communication apparatus provided with the antenna device.
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Citations
16 Claims
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1. An antenna device, comprising:
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a variable reactance circuit having a reactance value variable on the basis of a control signal;
an RF circuit having a matching circuit at an output side;
an antenna element having one end to which an electrical signal is fed from the RF circuit and the other end terminated by the variable reactance circuit; and
a reactance and matching control circuit that outputs the control signal for setting the reactance value of the variable reactance circuit to a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification