Device using a filter with resonators

A filter device comprising:

• an input electronic circuit having an output admittance Yin;
• an output electronic circuit having an input admittance Yout;
• a filter having a differential input connected to the input circuit and comprising a plurality of resonators of first and second types connected between an input and an output of the filter, the resonators of the first type having a resonant frequency Fr1 and an antiresonant frequency Fa1 and the resonators of the second type having a resonant frequency Fr2 and an antiresonant frequency Fa2 respectively different from Fr1 and Fa1;
• and
• a differential output connected to the output circuit;
• wherein
• the reciprocal of the real part of the admittance Yin (1/Re{Yin}) and the reciprocal of the real part of the admittance Yout (1/Re{Yout}) are greater than k times the value of the geometric mean of characteristic impedances of the resonators, k being a number at least equal to 2;
• and
• the frequency differences Fa1−Fr1 and Fa2−Fr2 are greater than k′ times the absolute value of the frequency difference Fr1−Fr2, k′ being a number at least equal to 2.