Band pass filter
AssigneeSkyworks Solutions, Inc.
InventorsHai H. Ta, Weimin Sun
Life of this patent
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Abstract
Aspects of this disclosure relate to a band pass filter that includes LC resonant circuits coupled to each other by a capacitor. A bridge capacitor can be in parallel with series capacitors, in which the series capacitors include the capacitor coupled between the LC resonant circuits. The bridge capacitor can create a transmission zero at a frequency below the passband of the band pass filter. The LC resonant circuits can each include a surface mount capacitor and a conductive trace of the substrate, and an integrated passive device die can include the capacitor. Band pass filters disclosed herein can be relatively compact, provide relatively good out-of-band rejection, and relatively low loss.
Claims20
A band pass filter comprising:
- a first LC resonant circuit;
- a second LC resonant circuit;
- capacitors arranged in series with each other, a capacitor of the capacitors being coupled between the first LC resonant circuit and the second LC resonant circuit;
- and
- a bridge capacitor coupled in parallel with the capacitors, the band pass filter having a pass band, and the bridge capacitor arranged to create a transmission zero at a frequency below the passband of the band pass filter.
A filter assembly comprising:
- a first LC resonant circuit including a first conductive trace of a substrate and a first surface mount capacitor on the substrate;
- a second LC resonant circuit including a second conductive trace of the substrate and a second surface mount capacitor on the substrate;
- and
- an integrated passive device die on the substrate, the integrated passive device die including a capacitor coupled between the first LC resonant circuit and the second LC resonant circuit;
- the capacitor, the first LC resonant circuit, and the second LC resonant circuit being included in a band pass filter.
A front end module comprising:
- a band pass filter including a first LC resonant circuit, a second LC resonant circuit, capacitors arranged in series with each other and including a capacitor coupled between the first LC resonant circuit and the second LC resonant circuit, and a bridge capacitor coupled in parallel with the capacitors, the bridge capacitor arranged to create a transmission zero below a passband of the band pass filter;
- a power amplifier;
- a low noise amplifier;
- and
- a transmit/receive switch configured to selectively couple the band pass filter to the power amplifier or the low noise amplifier.
Dependencies are inferred from the claim text.