Diplexer, and high-frequency switch and antenna duplexer using the same
First Claim
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1. A diplexer for multiplexing and demultiplexing radio waves of different frequency bands, comprising:
- a low-pass filter placed between a first terminal connected to an antenna side and a second terminal for transmitting and receiving a signal of a low frequency band, the low-pass filter passing only the signal of a low frequency band; and
a high-pass filter placed between the first terminal and a third terminal for transmitting and receiving a signal of the high frequency band, the high-pass filter passing only the signal of the high frequency band, wherein the low-pass filter includes at least two resonant circuits to provide at least attenuation poles at a high-frequency side of a passband.
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Abstract
A diplexer capable of passing signals of a high frequency band without being attenuated over a wide frequency band, and a high-frequency switch using the diplexer are provided. The diplexer includes a low-pass filter 82 having a parallel resonant circuit formed by a first capacitor C1 and a first inductor L1 and a serial resonant circuit formed by a second capacitor C2 and a second inductor L2. With this structure, two attenuation poles are provided in the low-pass filter 82. Thus, a passband of a high-pass filter 83 can be widened.
43 Citations
28 Claims
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1. A diplexer for multiplexing and demultiplexing radio waves of different frequency bands, comprising:
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a low-pass filter placed between a first terminal connected to an antenna side and a second terminal for transmitting and receiving a signal of a low frequency band, the low-pass filter passing only the signal of a low frequency band; and
a high-pass filter placed between the first terminal and a third terminal for transmitting and receiving a signal of the high frequency band, the high-pass filter passing only the signal of the high frequency band, wherein the low-pass filter includes at least two resonant circuits to provide at least attenuation poles at a high-frequency side of a passband. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A high-frequency switch for switching transmission and reception of radio waves of different frequency bands, comprising:
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a diplexer for transmitting and receiving the radio waves of the different frequency bands via a first terminal connected to an antenna side for multiplexing and demultiplexing the radio waves;
a low-frequency transmission and reception switching circuit connected to a second terminal included in the diplexer for transmitting and receiving a signal of a low frequency band; and
a high-frequency transmission and reception switching circuit connected to a third terminal included in the diplexer for transmitting and receiving a signal of a high frequency band, the diplexer including;
a low-pass filter placed between the first terminal and the second terminal for passing only the signal of the low frequency band; and
a high-pass filter placed between the first terminal and the third terminal for passing only the signal of the high frequency band, and the low-pass filter having at least two resonant circuits to provide at least two attenuation poles at a high-frequency side of a passband. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. An antenna duplexer for simultaneously carrying out transmission and reception of radio waves of different frequency bands, comprising:
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a diplexer for transmitting and receiving the radio waves of the different frequency bands via a first terminal connected to an antenna side for multiplexing and demultiplexing the radio waves;
a first duplexer connected to a second terminal included in the diplexer for transmitting and receiving a signal of a low frequency band; and
a second duplexer connected to a third terminal included in the diplexer for transmitting and receiving a signal of a high frequency band;
the diplexer including;
a low-pass filter placed between the first terminal and the second terminal for passing only the signal of the low frequency band; and
a high-pass filter placed between the first terminal and the third terminal for passing only the signal of the high frequency band, and the low pass filter having at least two resonant circuits to provide at least two attenuation poles at a high-frequency side of a passband. - View Dependent Claims (23, 24, 25, 26)
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27. A wireless communications device for carrying out transmission and reception of radio waves of different frequency bands, comprising
a high-frequency switch for switching the transmission and reception of the radio waves of the different frequency bands, the high-frequency switch including: -
a diplexer for transmitting and receiving the radio waves of the different frequency bands via a first terminal connected to an antenna side for multiplexing and demultiplexing the radio waves;
a low-frequency transmission and reception switching circuit connected to a second terminal included in the diplexer for transmitting and receiving a signal of a low frequency band; and
a high-frequency transmission and reception switching circuit connected to a third terminal included in the diplexer for transmitting and receiving a signal of a high frequency band, the diplexer including;
a low-pass filter placed between the first terminal and the second terminal for passing only the signal of the low frequency band; and
a high-pass filter placed between the first terminal and the third terminal for passing only the signal of the high frequency band, and the low-pass filter having at least two resonant circuits to provide at least two attenuation poles (AP1, AP2) at a high-frequency side of a passband.
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28. A wireless communications device for carrying out transmission and reception of radio waves of different frequency bands, comprising
an antenna duplexer for simultaneously carrying out transmission and reception of radio waves of different frequency bands, the antenna duplexer including: -
a diplexer for transmitting and receiving the radio waves of the different frequency bands via a first terminal connected to an antenna side for multiplexing and demultiplexing the radio waves;
a first duplexer connected to a second terminal included in the diplexer for transmitting and receiving a signal of a low frequency band; and
a second duplexer connected to a third terminal included in the diplexer for transmitting and receiving a signal of a high frequency band, the diplexer including;
a low-pass filter placed between the first terminal and the second terminal for passing only the signal of the low frequency band; and
a high-pass filter placed between the first terminal and the third terminal for passing only the signal of the high frequency band, and the low pass filter having at least two resonant circuits to provide at least two attenuation poles at a high-frequency side of a passband.
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Specification