Diode tuned resonator filter
First Claim
Patent Images
1. A filter, comprising:
- a transmission line resonator;
a reactance; and
coupling means for selectively coupling said reactance in parallel with a portion of said transmission line resonator such that said reactance is conductively coupled to a part of said transmission line resonator between two coupling points along a part of the length of the transmission line resonator.
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Abstract
A transmission line resonator is disclosed which has a resonance frequency that is electrically controllable by control voltage. A reactive circuit is coupled in parallel between two coupling points on the transmission line resonator. The reactive value of the reactive circuit is changed by the control voltage. The reactive circuit can be inductive or capacitive. The control voltage can switch the reactive circuit in parallel with a part of the transmission line resonator between the coupling points, or can control the capacitance value of a capacitance diode disposed in parallel with a part of the transmission line resonator between the coupling points.
55 Citations
14 Claims
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1. A filter, comprising:
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a transmission line resonator; a reactance; and coupling means for selectively coupling said reactance in parallel with a portion of said transmission line resonator such that said reactance is conductively coupled to a part of said transmission line resonator between two coupling points along a part of the length of the transmission line resonator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A radio frequency filter, comprising:
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at least two transmission line resonator circuits; at least one of said transmission line resonator circuits being controllable by a control terminal to which a control voltage is selectively applied to change the resonance frequency thereof; a reactance coupled in parallel between two coupling points along a part of the length of the controllable transmission line resonator circuit, said control terminal being operatively coupled to said reactance to change the value of the reactance in response to a selectively applied control voltage. - View Dependent Claims (10, 11, 12, 13)
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14. A transmission line resonator having a resonance frequency which is controlled by a selective application of a control voltage, comprising:
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a PIN diode having a cathode electrically coupled to a first point on the transmission line resonator and an anode which is selectively connectable to the control voltage; and a reactance having one end electrically coupled to a second point on the transmission line resonator and another end electrically connected to said anode, said first and second coupling points including only a part of the length of the transmission line resonator, whereby said reactance is conductively coupled in parallel to said part of the length of the transmission line resonator only when said anode is connected to the control voltage and said PIN diode conducts to change the resonance frequency of the transmission line resonator.
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Specification