Methods and circuits for detuning a filter and matching network at the output of a power amplifier
First Claim
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1. Circuitry comprising:
- a first power amplifier (PA) configured to operate in one of an ON state, in which the first PA amplifies one or more signals about a first frequency band, or an OFF state;
a first filter coupled to the first PA and configured to pass signals about the first frequency band between an output of the first PA and a first antenna node;
a second power amplifier (PA) configured to operate in one of an ON state, in which the second PA amplifies one or more signals about a second frequency band that is different from the first frequency band, or an OFF state;
a second filter coupled to the second PA and configured to, in the ON state of the first PA, exhibit a first frequency response in order to attenuate signals about one or more harmonic frequencies of the first frequency band, and in the OFF state of the first PA, exhibit a second frequency response in order to pass signals about the second frequency band between an output of the second PA and a second antenna node.
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Abstract
In transmitter modules or power amplifier (PA) modules there is at least a possible path for a second and even a third harmonic of a low band to crossover unfiltered into the high band path and reach the antenna and hence cross band isolation is necessary. Forward isolation is necessary in order to limit the input crossing over the PAs into the antenna port. According to the methods and the circuits such cross band isolation and forward isolation is improved by detuning the filter and matching network at the output of the PA. The circuit comprises a trap at the harmonic frequencies of the low band thereby at least reducing the impacts of the cross band and forward isolation.
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Citations
7 Claims
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1. Circuitry comprising:
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a first power amplifier (PA) configured to operate in one of an ON state, in which the first PA amplifies one or more signals about a first frequency band, or an OFF state; a first filter coupled to the first PA and configured to pass signals about the first frequency band between an output of the first PA and a first antenna node; a second power amplifier (PA) configured to operate in one of an ON state, in which the second PA amplifies one or more signals about a second frequency band that is different from the first frequency band, or an OFF state; a second filter coupled to the second PA and configured to, in the ON state of the first PA, exhibit a first frequency response in order to attenuate signals about one or more harmonic frequencies of the first frequency band, and in the OFF state of the first PA, exhibit a second frequency response in order to pass signals about the second frequency band between an output of the second PA and a second antenna node. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification