A method of tuning the stopband attenuation of an absorptive bandstop filter having at least a first and second resonator, where the first resonator includes a first tuning element that exhibits a first resonant frequency, the second resonator includes a second tuning element that exhibits a second resonant frequency, and the tuning elements are used to adjust the corresponding resonant frequencies, includes 1) adjusting the first resonant frequency using the first tuning element; and 2) adjusting the second resonant frequency using the second tuning element, such that both resonant frequencies are coordinated to obtain a selected stopband attenuation level and to thus realize a frequency-selective variable attenuator.