Filtering arrangement with impedance step resonators
First Claim
1. A radio-frequency filter for a radio apparatus operating both on a first frequency band and on a second frequency band higher than the first frequency band, the filter comprising:
- at least one transmission line resonator having a first section with a first impedance and a second section coupled to the first section and with a second impedance different from the first impedance;
the magnitudes of the first and second impedances selected such that said transmission line resonator has a fundamental resonating frequency at substantially said first frequency band and a harmonic resonating frequency at substantially said second frequency band.
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Accused Products
Abstract
A radio-frequency filter for a radio apparatus operating on two frequency bands is based on impedance step resonators, wherein two interconnected resonator sections (L2, L1) having different impedances are dimensioned such that the resonator'"'"'s fundamental resonating frequency (f0) is on the lower operating frequency band and a certain harmonic resonating frequency (fs1) is on the higher operating frequency band. The filter may have separate ports (port 2, port 3) for the signals of the different frequency bands and they can be isolated from each other using additional filtering (LC1, LC2).
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Citations
8 Claims
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1. A radio-frequency filter for a radio apparatus operating both on a first frequency band and on a second frequency band higher than the first frequency band, the filter comprising:
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at least one transmission line resonator having a first section with a first impedance and a second section coupled to the first section and with a second impedance different from the first impedance; the magnitudes of the first and second impedances selected such that said transmission line resonator has a fundamental resonating frequency at substantially said first frequency band and a harmonic resonating frequency at substantially said second frequency band. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A dual band/dual mode radio system having a first operating frequency band and a second operating frequency band higher than the first frequency band, the system including a filter comprising impedance step resonators, each resonator having an open end and a short circuited end, the impedance of the open end being different from the impedance at the short circuited end, and where the fundamental frequency of the impedance step resonators is at the first operating frequency band of the radio system and a certain harmonic resonating frequency is at the second operating frequency band of the radio system.
Specification