Harmonic suppressed bandwidth and center frequency tunable capacitive coupled band pass filter
AssigneeHRL Laboratories, LLC
InventorHanseung Lee
Life of this patent
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Abstract
A filter comprising a linear array of a plurality of TL-inspired T-networks connected in series by capacitors, each TL-inspired T-network typically comprising a pair of conventional transmission lines connected in series with a circuit comprising pair of inductors and a single capacitor, the conventional transmission lines associated with each TL-inspired T-network being optionally combinable together or with conventional transmission lines in neighboring TL-inspired T-networks, wherein the circuit comprising a pair of inductors and a single capacitor is an artificial transmission line providing target characteristic impedance, which is same as that of the conventional transmission lines, and phase delay.
Claims16
A filter having a tunable center frequency and tunable bandwidth capability, the filter comprising a linear array of a plurality of TL-inspired T-networks connected in series by tunable capacitors, each TL-inspired T-network comprising a pair of conventional transmission lines connected in series with a circuit comprising a pair of inductors and a single capacitor, wherein the circuit comprising a pair of inductors and a single capacitor simulates an artificial transmission line providing a target characteristic impedance and a tunable phase delay.
A filter comprising a plurality of TL-inspired T-networks, the plurality of TL-inspired T-networks being connected in series by tunable capacitors, the plurality of TL-inspired T-networks each comprising a pair of conventional transmission lines connected in series with a network of reactance devices.
A method of designing or making a harmonic suppressed bandwidth and center frequency tunable capacitive coupled band pass filter comprising:
- a. selecting a prior art filter design to be converted to the harmonic suppressed bandwidth and center frequency tunable capacitive coupled band pass filter, the prior art filter design comprising a series of conventional transmission lines connected in series with capacitors,
- b. replacing one or more of the conventional transmission lines with a pair of shorter or different conventional transmission lines each having less than one-half the phase delay of the one or more of the conventional transmission lines being replaced, and
- c. inserting a lumped circuit of reactance devices between the pair of shorter or different conventional transmission lines each having less than one-half the phase delay of the conventional transmission line or lines being replaced.
An improved transmission line that inhibits the transmission of harmonics compared to a conventional transmission line, the improved transmission line comprising:
- a. a pair of short conventional transmission lines, each short conventional transmission line being shorter than said conventional transmission line and each having less than one-half the phase delay of said conventional transmission line, and
- b. a lumped circuit of reactance devices installed between the pair of short conventional transmission lines, the lumped circuit having a lumped circuit phase delay and wherein the lumped circuit phase delay plus a total phase delay of the pair of short conventional transmission lines substantially equals the phase delay of said conventional transmission line.
Dependencies are inferred from the claim text.