Tunable filtering using conductively coupled resonances

A method of filtering radio frequency signals, the method comprising:

• filtering a first signal with a filter circuit, the filter circuit having a first frequency response that includes a plurality of stopbands;
• adjusting a reactance of a variable reactance of the filter circuit to change two or more notch frequencies of a frequency response of the filter circuit responsive to filtering the first signal;
• and
• filtering a second signal responsive to adjusting the reactance of the variable reactance.

A front-end module comprising:

• a filter circuit including
• a first node;
• a second node;
• a variable reactance coupled to the first node, the variable reactance including at least one impedance of a first type;
• a first impedance coupled to the first node, the first impedance being of a second type of impedance different than the first type;
• a second impedance of the second type coupled between the variable reactance and the first impedance;
• and
• a third impedance of the second type coupled at a first end to the first impedance and the second impedance, and coupled at a second end to the second node, the variable reactance being configured to operate in a plurality of resonant modes that each correspond to a resonant frequency between the variable reactance and reactances of one or more elements of a set including the first impedance, the second impedance, and the third impedance.