Patent ID: 7915977

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