Filter device for suppressing harmonics in radio frequency signals when dual frequencies exist
First Claim
1. Filter device (3) intended for suppressing harmonics in radio frequency signals (S1,S2,S3,S4), comprising a first filter (3b) with fixed characteristic, and a second filter (3a,90,110), which is arranged in series with the first filter (3b), characterized in that the second filter (3a,90,110) is switchable and comprises at least one resonance circuit device (22,24,94,122,124) with a first and a second terminal, where the first terminal is connected to a transmission conducting element (25,96,125) included in the resonance circuit device, and the second terminal is connected to a reference potential (VREF), where the resonance circuit device (22,24,94,122,124) comprises:
- firstly, a first parallel connection of a first reactive element (L22,L24,L94,C122,C124) and at least one reversible PIN-diode (D22), andsecondly, a second reactive element (C21,C23,C93,L122,L124), where it is arranged in series with the first parallel connection, the second, switchable filter (3a,90,110) being arranged;
to, in a first mode, provide good transmission of the radio frequency signal (S1,S3) in a first, lower, basic frequency band (51,81) and suppress at least one order of harmonics corresponding to this first basic frequency band (51,81), andto, in a second mode, provide good transmission of the radio frequency signal (S2,S4) in a second, higher, basic frequency band (61,91), the first filter (3b) suppressing at least one order of harmonics (62,92) corresponding to this second basic frequency band (61,91).
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Accused Products
Abstract
The present invention relates to a power amplifier device (10), switchable for at least two separate basic frequency bands, for radio frequency signals with effective suppression of harmonics, where harmonics, corresponding to a first basic frequency band, can be permitted to overlap the frequency range of at least one second basic frequency band. The power amplifier device (10) comprises a power amplifier (1) and an impedance matching circuit (2), switchable by means of a PIN-diode, which provides a load impedance adapted to each individual basic frequency band. Furthermore, the power amplifier device comprises a filter device (3) comprising a fixed low-pass filter (3b) and a switchable filter (3b) acting as an engageable and disengageable notch filter, which comprises at least one reversible PIN-diode. This switchable filter (3a) allows to pass, in a first mode, signals in the first basic frequency band and suppresses at the same time at least one order of harmonics corresponding to this basic frequency band. In a second mode, the second basic frequency band is transmitted without appreciable losses, and harmonics are suppressed by the fixed low-pass filter (3a).
57 Citations
15 Claims
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1. Filter device (3) intended for suppressing harmonics in radio frequency signals (S1,S2,S3,S4), comprising a first filter (3b) with fixed characteristic, and a second filter (3a,90,110), which is arranged in series with the first filter (3b), characterized in that the second filter (3a,90,110) is switchable and comprises at least one resonance circuit device (22,24,94,122,124) with a first and a second terminal, where the first terminal is connected to a transmission conducting element (25,96,125) included in the resonance circuit device, and the second terminal is connected to a reference potential (VREF), where the resonance circuit device (22,24,94,122,124) comprises:
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firstly, a first parallel connection of a first reactive element (L22,L24,L94,C122,C124) and at least one reversible PIN-diode (D22), and secondly, a second reactive element (C21,C23,C93,L122,L124), where it is arranged in series with the first parallel connection, the second, switchable filter (3a,90,110) being arranged; to, in a first mode, provide good transmission of the radio frequency signal (S1,S3) in a first, lower, basic frequency band (51,81) and suppress at least one order of harmonics corresponding to this first basic frequency band (51,81), and to, in a second mode, provide good transmission of the radio frequency signal (S2,S4) in a second, higher, basic frequency band (61,91), the first filter (3b) suppressing at least one order of harmonics (62,92) corresponding to this second basic frequency band (61,91). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Power amplifier device (10) for radio frequency signals, comprising:
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a power amplifier (1); an impedance matching circuit (2) arranged at the outlet of the power amplifier (1), and a filter device (3) connected to the outlet of the impedance matching circuit (2) for suppression of harmonics, the function of which corresponds to a combination of; a first filter (3b) with fixed characteristic, and a second filter (3a,90,110) arranged in series with the first filter (3b), characterized in that the power amplifier device (10) has at least two modes, where the modes correspond to adapting the properties of the power amplifier device (10) to at least one basic frequency band (51,61) each, and that the second filter (3a,90,110) is switchable and arranged; in a first mode of said modes, to provide good transmission for a first, lower basic frequency band (51,81) and suppress at least one order of harmonics corresponding to this first basic frequency band (51,81), and in a second mode of said modes, to provide good transmission for a second, higher basic frequency band (61,91). - View Dependent Claims (13, 14)
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15. Mobile station (100) in a cellular communication network, where the mobile station is intended for communication with at least one base station over at least two alternative, separate radio frequency bands, the mobile station comprising at least one power amplifier device (10) for radio frequency signals, comprising:
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a power amplifier (1); an impedance matching circuit (2) arranged at the outlet of the power amplifier (1), and a filter device (3) connected to the outlet of the impedance matching circuit (2) for suppression of harmonics, the function of which corresponding to a combination of; a first filter (3b) with fixed characteristic, and a second filter (3a,90,110) arranged in series with the first filter (3b), characterized in that the power amplifier device (10) has at least two modes, where the modes correspond to adapting of the properties of the power amplifier device (10) to at least one basic frequency band (51,61) each, and that the second filter (3a,90,110) is switchable and arranged; in a first mode of said modes, to provide good transmission of a first, lower basic frequency band (51,81), and suppress at least one order of harmonics corresponding to this first basic frequency band (51,81), and in a second mode of said modes, to provide good transmission of a second, higher basic frequency band (61,91).
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Specification