Antenna device and radio equipment having the same
First Claim
1. An antenna device which can transmit and receive radio waves in two different frequency bands including a lower frequency band and a higher frequency band, comprising:
- an antenna conductor portion having a resonance frequency which is lower than a center frequency in the higher frequency band and is higher than a center frequency in the lower frequency band; and
an LC parallel resonance circuit connected in series with a power supply side of the antenna conductor portion, wherein the LC parallel resonance circuit is configured so as to resonate at a frequency approximately equal to the center frequency in the lower frequency band, causing the antenna conductor portion to resonate at the center frequency in the lower frequency band, and so as to provide a capacitance for causing the antenna conductor portion to resonate at the center frequency in the higher frequency band.
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Accused Products
Abstract
An LC parallel resonance circuit is connected in series with the power supply side of the antenna conductor portion. The antenna conductor portion is configured so as to resonate at a frequency slightly lower than the center frequency in the higher frequency band of two frequency bands for transmitting and receiving radio waves. The LC parallel resonance circuit is configured so as to resonate substantially at the center frequency in the lower frequency band for transmitting and receiving a radio wave and be capable of providing to the antenna conductor portion a capacitance for causing the antenna conductor portion to resonate at the center frequency in the higher frequency band. Thus, a circuit for changing the upper and lower frequency bands is not needed. Such a change-over circuit, which is complicated, causes problems in that the conduction loss increases, and the antenna sensitivity deteriorates. Without need of the change-over circuit, the conduction loss can be reduced, the antenna sensitivity can be enhanced and costs can be reduced.
199 Citations
22 Claims
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1. An antenna device which can transmit and receive radio waves in two different frequency bands including a lower frequency band and a higher frequency band, comprising:
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an antenna conductor portion having a resonance frequency which is lower than a center frequency in the higher frequency band and is higher than a center frequency in the lower frequency band; and
an LC parallel resonance circuit connected in series with a power supply side of the antenna conductor portion, wherein the LC parallel resonance circuit is configured so as to resonate at a frequency approximately equal to the center frequency in the lower frequency band, causing the antenna conductor portion to resonate at the center frequency in the lower frequency band, and so as to provide a capacitance for causing the antenna conductor portion to resonate at the center frequency in the higher frequency band. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22)
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16. Radio equipment comprising at least one of a transmitter and a receiver and an antenna device coupled to the at least one of a transmitter and receiver, the antenna device being capable of transmitting and receiving radio waves in two different frequency bands including a lower frequency band and a higher frequency band, the antenna device comprising:
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an antenna conductor portion having a resonance frequency which is lower than a center frequency in the higher frequency band and is higher than a center frequency in the lower frequency band; and
an LC parallel resonance circuit connected in series with a power supply side of the antenna conductor portion, wherein the LC parallel resonance circuit is configured so as to resonate at a frequency approximately equal to the center frequency in the lower frequency band, causing the antenna conductor portion to resonate at the center frequency in the lower frequency band, and so as to provide a capacitance for causing the antenna conductor portion to resonate at the center frequency in the higher frequency band.
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Specification