Interference rejection RF filters
First Claim
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1. An apparatus comprising an RF filter structure, which comprises:
- a plurality of resonators comprising a pair of weakly coupled resonators;
a plurality of cross-coupling capacitive structures, wherein each of the plurality of cross-coupling capacitive structures is coupled between two of the plurality of resonators; and
a plurality of egress/ingress capacitive structures, wherein a first portion of the plurality of egress/ingress capacitive structures is coupled between the plurality of resonators and a first connection node, and a second portion of the plurality of egress/ingress capacitive structures is coupled between the plurality of resonators and a second connection node, wherein;
a corresponding coupling coefficient of each of the plurality of egress/ingress capacitive structures is adjustable;
a first tunable RF filter comprises at least a portion of the plurality of resonators, at least a portion of the plurality of cross-coupling capacitive structures, and at least a portion of the plurality of egress/ingress capacitive structures;
a frequency response of the first tunable RF filter is a bandpass filter response with a first notch filter response, which has a first notch frequency, such that the bandpass filter response has a center frequency; and
the first notch frequency is equal to a first sum plus a first difference, such that the first sum is equal to a sum of the center frequency and a harmonic of a local oscillator frequency, and the first difference is equal to a difference between the center frequency and the local oscillator frequency.
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Abstract
RF communications circuitry includes an RF filter structure, which includes a group of resonators, a group of cross-coupling capacitive structures, and a group of egress/ingress capacitive structures, is disclosed. Each of the group of cross-coupling capacitive structures is coupled between two of the group of resonators. A first portion of the group of egress/ingress capacitive structures is coupled between a first connection node and the group of resonators. A second portion of the group of egress/ingress capacitive structures is coupled between a second connection node and the group of resonators.
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Citations
29 Claims
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1. An apparatus comprising an RF filter structure, which comprises:
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a plurality of resonators comprising a pair of weakly coupled resonators; a plurality of cross-coupling capacitive structures, wherein each of the plurality of cross-coupling capacitive structures is coupled between two of the plurality of resonators; and a plurality of egress/ingress capacitive structures, wherein a first portion of the plurality of egress/ingress capacitive structures is coupled between the plurality of resonators and a first connection node, and a second portion of the plurality of egress/ingress capacitive structures is coupled between the plurality of resonators and a second connection node, wherein; a corresponding coupling coefficient of each of the plurality of egress/ingress capacitive structures is adjustable; a first tunable RF filter comprises at least a portion of the plurality of resonators, at least a portion of the plurality of cross-coupling capacitive structures, and at least a portion of the plurality of egress/ingress capacitive structures; a frequency response of the first tunable RF filter is a bandpass filter response with a first notch filter response, which has a first notch frequency, such that the bandpass filter response has a center frequency; and the first notch frequency is equal to a first sum plus a first difference, such that the first sum is equal to a sum of the center frequency and a harmonic of a local oscillator frequency, and the first difference is equal to a difference between the center frequency and the local oscillator frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus comprising an RF filter structure, which comprises:
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a plurality of resonators; a plurality of cross-coupling capacitive structures, wherein each of the plurality of cross-coupling capacitive structures is coupled between two of the plurality of resonators; and a plurality of egress/ingress capacitive structures, wherein a first portion of the plurality of egress/ingress capacitive structures is coupled between the plurality of resonators and a first connection node, and a second portion of the plurality of egress/ingress capacitive structures is coupled between the plurality of resonators and a second connection node, such that; a first tunable RF filter comprises at least a portion of the plurality of resonators, at least a portion of the plurality of cross-coupling capacitive structures, and at least a portion of the plurality of egress/ingress capacitive structures, wherein the first connection node is an input to the first tunable RF filter and the second connection node is an output from the first tunable RF filter; a frequency response of the first tunable RF filter is a bandpass filter response having a center frequency, such that the frequency response of the first tunable RF filter is the bandpass filter response with a first notch filter response, which has a first notch frequency; the bandpass filter response is associated with a first of the plurality of egress/ingress capacitive structures and the first notch filter response is associated with a second of the plurality of egress/ingress capacitive structures; and a coupling coefficient of the first of the plurality of egress/ingress capacitive structures is greater than a coupling coefficient of the second of the plurality of egress/ingress capacitive structures. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. An apparatus comprising interference detection circuitry, control circuitry, and an RF filter structure, which comprises:
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a plurality of resonators; a plurality of cross-coupling capacitive structures, wherein each of the plurality of cross-coupling capacitive structures is coupled between two of the plurality of resonators; and a plurality of egress/ingress capacitive structures, wherein a first portion of the plurality of egress/ingress capacitive structures is coupled between the plurality of resonators and a first connection node, and a second portion of the plurality of egress/ingress capacitive structures is coupled between the plurality of resonators and a second connection node, such that; a first tunable RF filter comprises at least a portion of the plurality of resonators, at least a portion of the plurality of cross-coupling capacitive structures, and at least a portion of the plurality of egress/ingress capacitive structures, wherein the first connection node is an input to the first tunable RF filter and the second connection node is an output from the first tunable RF filter; a frequency response of the first tunable RF filter is a bandpass filter response having a center frequency, such that the frequency response of the first tunable RF filter is the bandpass filter response with a first notch filter response, which has a first notch frequency; the interference detection circuitry is configured to detect a frequency of an interfering signal, such that the first notch frequency is about equal to the frequency of the interfering signal; and the control circuitry is configured to select the center frequency and the first notch frequency using a first filter control signal based on the interfering signal. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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Specification