Filter circuit with a notch filter
AssigneeRf360 Europe GmbH
InventorRoeland HEIJNA
Life of this patent
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Abstract
A filter circuit comprises in a signal line a band filter (BF) allowing to let pass a useful frequency band and a notch filter (NF) circuited in series to the band filter for filtering out a stop band frequency. The notch filter comprises a series circuit of a number of parallel shunt elements (SE1 . . . SE6) wherein each shunt element is shifted infrequency against the other shunt elements that the frequencies thereof are distributed (f1 . . . F6) over a notch band. All shunt elements may be realized as a SAW one-port resonator (TRNF) including regions with different pitches.
Claims9
A filter circuit comprising in a signal line (SL)
- a band filter (BF) allowing to let pass a useful frequency band and
- a notch filter (NF) circuited in series to the band filter for filtering out a stop band frequency
- wherein
- the notch filter comprises a series circuit of a number n of parallel shunt elements (SE),
- each shunt element (SE1, SE2, . . . SEn) being shifted in frequency against the other shunt elements that all shunt elements are distributed over a notch band
- the notch filter (NF) provides the notch band (NB).
A PAMiD frontend module (FEM) comprising:
- a filter circuit comprising in a signal line (SL) a band filter (BF) allowing to let pass a useful frequency band and a notch filter (NF) circuited in series to the band filter for filtering out a stop band frequency, wherein the notch filter comprises a series circuit of a number n of parallel shunt elements (SE), each shunt element (SE1, SE2, . . . SEn) being shifted in frequency against the other shunt elements that all shunt elements are distributed over a notch band and the notch filter (NF) provides the notch band (NB), and
- a power amplifier (PA) and a matching circuit, wherein a further filter circuit operating in a neighbored band is part of the PAMiD frontend module or of a different device operating together with the PAMiD frontend module and wherein the notch band (NB) is centered on the neighbored band.
Dependencies are inferred from the claim text.