Front-end topology for multiband multimode communication engines
First Claim
1. A method for selecting a frequency band in a multiband communications device, the communications device having one or more antennas for conveying radio frequencies, and a front-end module having one or more nodes operatively connected to said one or more antennas, the front end module comprising:
- a first bandpass filter disposed in a first signal path for filtering signals in a first frequency band, the first bandpass filter having a first end and a second end, the first end operatively connected to said one or more antennas; and
a second bandpass filter disposed in a second signal path for filtering signals in a second frequency band different from the first frequency band;
the second bandpass filter operatively connected to said one or more antennas, said method comprising;
disposing a switch at the second end of the first bandpass filter independent of the second signal path for enabling or disabling the first signal path.
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Abstract
The combination of filters and switches is used to solve the non-linearity problems in GSM/W-CDMA transceiver front-end wherein one common antenna is used for both the GSM mode and the W-CDMA mode. In particular, separate Rx/Tx paths and switches in the Rx paths are used to provide cross-band isolation between bands. All of the switches in the transceiver are disposed after the filters in that no switches are disposed between the filters and the antenna. Furthermore, bandpass filters are matched to one common node even if they are only disconnected at the output as long as the impedance at the output can be controlled.
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Citations
36 Claims
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1. A method for selecting a frequency band in a multiband communications device, the communications device having one or more antennas for conveying radio frequencies, and a front-end module having one or more nodes operatively connected to said one or more antennas, the front end module comprising:
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a first bandpass filter disposed in a first signal path for filtering signals in a first frequency band, the first bandpass filter having a first end and a second end, the first end operatively connected to said one or more antennas; and
a second bandpass filter disposed in a second signal path for filtering signals in a second frequency band different from the first frequency band;
the second bandpass filter operatively connected to said one or more antennas, said method comprising;
disposing a switch at the second end of the first bandpass filter independent of the second signal path for enabling or disabling the first signal path. - View Dependent Claims (2, 3, 4)
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5. A transceiver for use in a communication device having one or more antennas for conveying radio frequency signals, said transceiver comprising:
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a first bandpass filter disposed in a first signal path for filtering signals in a first frequency band, the first bandpass filter having a first end and a second end, the first end operatively connected to said one or more antennas;
a second bandpass filter disposed in a second signal path for filtering signals in a second frequency band different from the first frequency band;
the second bandpass filter operatively connected to said one or more antennas; and
a switch disposed at the second end of the first bandpass filter independent of the second signal path for enabling or disabling the first signal path. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A communications device comprising:
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one or more antennas for conveying radio frequency signals; and
a transceiver, wherein the transceiver comprises;
a first bandpass filter disposed in a first signal path for filtering signals in a first frequency band, the first bandpass filter having a first end and a second end, the first end operatively connected to said one or more antennas;
a second bandpass filter disposed in a second signal path for filtering signals in a second frequency band different from the first frequency band;
the second bandpass filter operatively connected to said one or more antennas; and
a switch disposed at the second end of the first bandpass filter independent of the second signal path for enabling or disabling the first signal path. - View Dependent Claims (31, 32, 33, 34, 35, 36)
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Specification