System and method for a radio frequency filter

An RF system comprising:

• a transmit path comprising a first tunable transmit band stop filter, a power amplifier having an input coupled to an output of the first tunable transmit band stop filter, and a transmit antenna port coupled to an output of the power amplifier, wherein the first tunable transmit band stop filter is configured reject a receive frequency and pass a transmit frequency;
• and
• a receive path comprising a first tunable receive band stop filter having an input coupled to a receive antenna port, and an LNA having an input coupled to an output of the first tunable receive band stop filter, wherein the first tunable receive band stop filter is configured reject the transmit frequency and pass the receive frequency,
• wherein the RF system further comprises a transmit antenna coupled to the transmit antenna port, and a receive antenna coupled to the receive antenna port.

An RF system comprising:

• a first transmit path comprising a first power amplifier, a first tunable transmit band stop filter coupled to an output of the first power amplifier, and a first adjustable transmit phase shifter/matching network coupled between the first tunable transmit band stop filter and an antenna port, wherein the first tunable transmit band stop filter is configured reject a second transmit frequency and pass a first transmit frequency, and the first adjustable transmit phase shifter/matching network is configured to transform a first impedance of the first tunable transmit band stop filter at the second transmit frequency from a first lower impedance to a first higher impedance at the antenna port;
• and
• a second transmit path comprising a second power amplifier, a second tunable transmit band stop filter coupled to an output of the second power amplifier, and a second adjustable transmit phase shifter/matching network coupled between the second tunable transmit band stop filter and the antenna port, wherein the second tunable transmit band stop filter is configured reject the first transmit frequency and pass the second transmit frequency, and the second adjustable transmit phase shifter/matching network is configured to transform a second impedance of the second tunable transmit band stop filter at the first transmit frequency from a second lower impedance to a second higher impedance at the antenna port.