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US 9,166,564 B2Granted
Wideband analog bandpass filter
AssigneeHittite Microwave Corporation
InventorMichael Koechlin
Life of this patent
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Abstract
A wideband bandpass filter includes an RF input terminal, an RF output terminal, a plurality of electrically tunable coupling capacitors coupled in series between the RF input and output terminals, and a plurality of resonating circuits each including an electrically tunable resonator capacitor coupled to one of the coupling capacitors. At least one resistance is coupled in series between at least one of the coupling capacitors for providing enhanced out of band rejection of the filter.
Claims24
A bandpass filter, comprising:
- a radio frequency (RF) input terminal;
- an RF output terminal;
- a plurality of electrically tunable coupling capacitors coupled in series between the RF input and output terminals;
- a plurality of resonating circuits each including an electrically tunable resonator capacitor and an inductor in parallel with the electrically tunable resonator capacitor, the electrically tunable resonator capacitor being coupled to at least one of the coupling capacitors;
- and
- at least one non-parasitic resistor coupled between the RF input and output terminals in series with at least one of the coupling capacitors, wherein the bandpass filter is configured to pass frequencies within a passband and reject frequencies outside of the passband, and wherein the at least one non-parasitic resistor is configured to provide enhanced out of band rejection of the bandpass filter by attenuating spurious responses outside of the passband of the bandpass filter.
3 more elements
A bandpass filter, comprising:
- an RF input terminal;
- an RF output terminal;
- a plurality of electrically tunable pairs of varactors coupled back-to-back in series between the RF input and output terminals;
- a plurality of resonating circuits each including an electrically tunable resonator capacitor and an inductor in parallel with the electrically tunable resonator capacitor, the electrically tunable resonator capacitor being coupled to at least one of the pairs of varactors;
- and
- at least one non-parasitic resistor coupled in series between the plurality of electrically tunable varactors, wherein the bandpass filter is configured to pass frequencies within a passband and reject frequencies outside of the passband, and wherein the at least one non-parasitic resistor is configured to provide enhanced out of band rejection of the bandpass filter by attenuating spurious responses outside of the passband of the bandpass filter.
3 more elements
Dependencies are inferred from the claim text.