Acoustic filter device with combined passband
An acoustic filter device for telecommunication devices includes a first acoustic band pass filter having a corresponding first passband and a second acoustic band pass filter having a corresponding second passband. The second acoustic band pass filter is connected in parallel with the first acoustic band pass filter to provide a combined passband including the first and second passbands.
1. An acoustic filter device for telecommunication devices, comprising:
a first acoustic band pass filter having a corresponding first passband; and
a second acoustic band pass filter having a corresponding second passband, the second acoustic band pass filter being connected in parallel with the first acoustic band pass filter to provide a combined passband comprising the first and second passbands,
wherein the first acoustic band pass filter has a corresponding first roll-off, and the second acoustic band pass filter has a corresponding second roll-off, and a portion of the first roll-off overlaps a portion of the second roll-off adjacent the first roll-off at least in part within a band-gap between the first and second passbands,
wherein the combined passband comprises a dip formed by non-overlapping portions of the first roll-off and the adjacent second roll-off, a lowest magnitude of signal in the dip being between about 3 dB and about 6 dB below a highest magnitude of signal in the combined passband.
2. The acoustic filter device of claim 1 , wherein a frequency range of the band-gap extends from a highest frequency of the first passband to a lowest frequency of the second passband.
3. The acoustic filter device of claim 1 , wherein each of the first and second acoustic band pass filters has ladder-type architecture.
4. The acoustic filter device of claim 1 , wherein each of the first and second acoustic band pass filters comprises a plurality of bulk acoustic wave (BAW) resonators.
5. The acoustic filter device of claim 4 , wherein each of the BAW resonators comprise one of a solidly mounted resonator (SMR) or a thin film bulk acoustic resonator (FBAR).
6. The acoustic filter device of claim 1 , wherein the first and second passbands correspond to predetermined frequency bands standard for telecommunication devices, respectively.
7. The acoustic filter device of claim 6 , wherein the predetermined frequency bands comprise at least one of a Long Term Evolution LTE standard, Global Navigation Satellite System (GNSS) standard, and a WiFi standard.
8. The acoustic filter device of claim 1 , wherein the first and second acoustic band pass filters have different bandwidths, respectively.
9. The acoustic filter device of claim 1 , further comprising:
a third acoustic band pass filter having a corresponding third passband, the third acoustic band pass filter being connected in parallel with the first and second acoustic band pass filters to provide the combined passband comprising the first, second and third passbands.
10. An acoustic filter device, comprising:
a first acoustic band pass filter having a corresponding first passband; and
a second acoustic band pass filter having a corresponding second passband, the second acoustic band pass filter being connected in parallel with the first acoustic band pass filter to provide a combined passband including the first and second passbands,
wherein a band-gap is positioned between the first passband and the second passband, the band-gap comprising a dip formed by non-overlapping portions of a first roll-off of the first acoustic band pass filter and a second roll-off of the second acoustic band pass filter,
wherein the dip formed by the non-overlapping portions of the first roll-off of the first acoustic band pass filter and the second roll-off of the second acoustic band pass filter has a lowest magnitude of signal between about 3 dB and about 6 dB below a highest magnitude of signal in the combined passband.
11. The acoustic filter device of claim 10 , wherein each of the first and second acoustic band pass filters has ladder-type architecture.
12. The acoustic filter device of claim 11 , wherein each of the first and second acoustic band pass filters comprises a receive filter configured to filter a radio frequency (RF) signal received from an antenna.
13. The acoustic filter device of claim 10 , wherein each of the first and second acoustic band pass filters comprises a transmit filter configured to filter a radio frequency (RF) signal sent by a transmitter.
14. An acoustic filter device, comprising:
a plurality of acoustic band pass filters connected in parallel to provide a combined passband, each of the acoustic band pass filters having a ladder-type architecture,
wherein the combined passband comprises a plurality of passbands corresponding to the plurality of acoustic band pass filters, respectively, and a plurality of dips in magnitude of signal in the combined passband substantially corresponding to band-gaps between adjacent passbands of the plurality of passbands within the combined passband, and
wherein the adjacent passbands have corresponding roll-offs, portions of which overlap, resulting in non-overlapping portions of the corresponding roll-offs forming the plurality of dips, respectively.