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US 5,917,387 AGranted
Filter having tunable center frequency and/or tunable bandwidth
AssigneeLucent Technologies Inc.
InventorsChristopher W. Rice, Harry R. Worstell
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AssigneeLucent Technologies Inc.
InventorsChristopher W. Rice, Harry R. Worstell
Estimating the term…
In an RF filter having an input terminal, an output terminal, a plurality of resonator elements, and a plurality of coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, techniques are disclosed for providing an RF filter having an electronically tunable center frequency and an electronically tunable bandwidth. According to a specific embodiment disclosed herein, a first shunt reactance is provided from the input terminal to ground, and a second shunt reactance is provided from the output terminal to ground. The values of the coupling reactances remain constant, while the values of the resonator elements, the first shunt reactance, and the second shunt reactance are tuned to provide a specified filter bandwidth and/or a specified center frequency. According to a further embodiment, such a tunable filter is fabricated on a physical substrate having a substantially constant dielectric constant per unit volume, and the coupling reactances include capacitors fabricated using the physical substrate.
An RF filter having an input terminal, an output terminal, a plurality of resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, CHARACTERIZED IN THAT the RF filter provides a tunable center frequency across a specified frequency range by only tuning one or more of the resonator elements, wherein normalized frequency response of the filter relative to the center frequency remains substantially constant over the specified frequency range.
An RF filter having an input terminal, an output terminal, a plurality of resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, CHARACTERIZED IN THAT the RF filter provides a tunable center frequency across a specified frequency range by only tuning one or more of the resonator elements, wherein the frequency response of the filter relative to the center frequency changes over the specified frequency range in accordance with a set of desired design parameters.
An RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element,
An RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element,
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, a first shunt reactance in shunt across the input terminal and ground, and a second shunt reactance in shunt across the output terminal and ground, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, a first shunt reactance shunted across the input terminal and ground, and a second shunt reactance shunted across the output terminal and ground, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, a first shunt reactance shunted across the input terminal and ground, and a second shunt reactance shunted across the output terminal and ground, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, a first shunt reactance shunted across the input terminal and ground, and a second shunt reactance shunted across the output terminal and ground, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, a first shunt reactance shunted across the input terminal and ground, and a second shunt reactance shunted across the output terminal and ground, the method CHARACTERIZED BY the steps of:
A method for use with an RF filter having an input terminal, an output terminal, a plurality of tunable resonator elements, and a plurality of fixed coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, a first shunt reactance shunted across the input terminal and ground, and a second shunt reactance from the output terminal to ground, the method CHARACTERIZED BY the steps of:
A method of implementing a tunable filter including a plurality of tunable resonators, each resonator including a plurality of shunt reactive elements, said method comprising:
Dependencies are inferred from the claim text.