摘要 |
A tuneable bandpass filter comprising a plurality of coupled resonators, the filter comprising a common structure comprising at least one common coupling or one common resonator; an upper loop comprising first and second end resonators coupled together by a signal path, the loop further comprising at least one further signal path extending between end resonators, the further signal path comprising at least one further resonator, the end resonators being coupled to the common structure; a lower loop comprising first and second end resonators coupled together by a signal path, the loop further comprising at least one further signal path extending between end resonators, the further signal path comprising at least one further resonator, the end resonators being coupled to the common structure; the resonators being coupled together such that the bandpass filter can be divided into a low pass sub filter and a high pass sub filter, one of the sub filters being arranged to receive the output of the other.
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