Transmitter filter arrangement for multiband mobile phone
First Claim
1. A method of filtering transceiver signals in a mobile terminal, the mobile terminal operable in at least one transmit frequency band and one receive frequency band separated from the transmit frequency band, wherein the mobile terminal has a signal source for providing transmit signal in the transmit frequency band, said method comprising the steps of:
- providing a signal path between the signal source and an antenna; and
providing a band-reject filter in the signal path so as to attenuate signal in the receive frequency band, wherein the band-reject filter comprises;
at least one series resonator operatively connected between the signal source and the antenna, the series resonator having a first end and an opposing second end, with the first end connected to the signal source;
at least one shunt resonator connecting between the second end of the series resonator and a grounding point, the shunt resonator and the series resonator forming an L-section; and
at least one inductor connected in parallel with the L-section.
7 Assignments
0 Petitions
Accused Products
Abstract
A filter arrangement for use in a multiband dual-mode mobile phone. In particular, the mobile phone is operable in a W-CDMA mode and a band-reject filter comprising at least a series and a shunt acoustic-wave resonators is used to create a deep notch at the receive frequency band. The band-reject filter further includes a plurality of inductive elements for matching static capacitance of the resonators at the passband frequency. The mobile phone is also operable in 1800 and 1900 GSM bands. The band-reject filter is operatively connected to a harmonic trap in order to eliminate the third harmonic of these GSM bands. The mobile phone is also operable in the lower GSM band, for which a harmonic filter can share an antenna path with the band-reject filter.
89 Citations
29 Claims
-
1. A method of filtering transceiver signals in a mobile terminal, the mobile terminal operable in at least one transmit frequency band and one receive frequency band separated from the transmit frequency band, wherein the mobile terminal has a signal source for providing transmit signal in the transmit frequency band, said method comprising the steps of:
-
providing a signal path between the signal source and an antenna; and
providing a band-reject filter in the signal path so as to attenuate signal in the receive frequency band, wherein the band-reject filter comprises;
at least one series resonator operatively connected between the signal source and the antenna, the series resonator having a first end and an opposing second end, with the first end connected to the signal source;
at least one shunt resonator connecting between the second end of the series resonator and a grounding point, the shunt resonator and the series resonator forming an L-section; and
at least one inductor connected in parallel with the L-section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A band-reject filter for use in a mobile terminal, the mobile terminal operable in at least one transmit frequency band and one receive frequency band separated from the transmit frequency band, wherein the mobile terminal has a signal source for providing transmit signal in the transmit frequency band, and a signal path between the signal source and an antenna, said filter comprising:
-
at least one series resonator operatively connected to the signal path between the signal source and the antenna, the series resonator having a first end and an opposing second end, with the first end connected to the signal source;
at least one shunt resonator connecting between the second end of the series resonator and a grounding point, the shunt resonator and the series resonator forming an L-section; and
at least one inductor connected in parallel with the L-section. - View Dependent Claims (13, 14, 15, 16)
-
-
17. A mobile terminal operable in at least one transmit frequency band and one receive frequency band separated from the transmit frequency band, said mobile terminal comprising:
-
a signal source for providing transmit signal in the transmit frequency band;
a signal path between the signal source and an antenna; and
a band-reject filter operatively connected to the signal path so as to attenuate signal in the receive frequency band, wherein the band-reject filter comprises;
at least one series resonator operatively connected between the signal source and the antenna, the series resonator having a first end and an opposing second end, with the first end connected to the transmission source;
at least one shunt resonator connecting between the second end of the series resonator and a reference point, the shunt resonator and the series resonator forming an L-section; and
at least one inductance connected in parallel with the L-section. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
-
Specification