Radio frequency system with tunable filters including tunable filter with mutually coupled inductors

A method of filtering radio frequency signals with tunable notch filtering, the method comprising:

• filtering an output signal from a power amplifier with a first tunable filter in a first state, the first tunable filter coupled between an output of the power amplifier and a multi-throw switch;
• processing an output signal from the first tunable filter with a signal path coupled between the multi-throw switch and an antenna switch;
• filtering an output signal from the antenna switch with a second tunable filter, the second tunable filter including a first inductor, a second inductor mutually coupled to the first inductor, and a tunable impedance circuit coupled to the first inductor;
• adjusting a state of the first tunable filter from the first state to a second state to thereby change a location of a first tunable notch of the first tunable filter in the frequency domain;
• and
• filtering the output of the power amplifier with the first tunable filter in the second state.

A wireless communication device with tunable notch filtering, the wireless communication device comprising:

• a power amplifier having an output;
• a radio frequency switch;
• a first tunable filter coupled between the output of the power amplifier and the radio frequency switch;
• an antenna switch coupled to the radio frequency switch by way of at least one radio frequency signal path;
• an antenna;
• and
• a second tunable filter coupled between the antenna switch and the antenna, the second tunable filter including a first inductor, a second inductor mutually coupled to the first inductor, and a tunable impedance circuit coupled to the first inductor.