Tunable filter with mutually coupled inductors

A tunable filter with tunable rejection, the tunable filter comprising:

• a first inductor;
• a second inductor mutually coupled with the first inductor;
• and
• a tunable capacitance circuit in parallel with the first inductor, the tunable capacitance circuit configured to adjust an effective capacitance in parallel with the first inductor to tune rejection of the tunable filter for at least two harmonics of interest.

A wireless communication system comprising:

• a power amplifier;
• a tunable filter electrically connected to an output of the power amplifier;
• the tunable filter including a first inductor, a second inductor mutually coupled with the first inductor, and a tunable capacitance circuit electrically connected to the first inductor, the tunable capacitance circuit including switches, each of the switches configured to adjust effective capacitance of the tunable capacitance circuit to tune rejection of the tunable filter for at least two harmonics of interest;
• and
• an antenna configured to transmit a radio frequency signal filtered by the tunable filter.