Cascaded baw filter dies of different technologies for performance improvement

A method of manufacturing a radio frequency (RF) filter circuit, comprising:

• forming a first RF circuit package, comprising:
• a first terminal externally accessible from the first RF circuit package;
• and
• a first piezoelectric substrate comprising one or more first acoustic resonators and a first main RF filter path section of a main RF filter path, the first main RF filter path section is coupled to the first terminal;
• forming a second RF circuit package, comprising:
• a second terminal externally accessible from the second RF circuit package;
• and
• a second piezoelectric substrate comprising one or more second acoustic resonators and a second main RF filter path section of the main RF filter path, the second main RF filter path section is coupled to the second terminal, wherein the first piezoelectric substrate is different than the second piezoelectric substrate;
• and
• coupling the first terminal of the first RF circuit package to the second terminal of the second RF circuit package such that the main RF filter path extends between the first terminal of the first RF circuit package and the second terminal of the second RF circuit package.

A user element comprising a radio frequency (RF) filter circuit, wherein the RF filter circuit comprises:

• a first RF circuit package, comprising:
• a first terminal externally accessible from the first RF circuit package;
• and
• a first piezoelectric substrate comprising one or more first acoustic resonators and a first main RF filter path section of a main RF filter path, the first main RF filter path section is coupled to the first terminal;
• and
• a second RF circuit package, comprising:
• a second terminal externally accessible from the second RF circuit package, wherein the first terminal of the first RF circuit package is coupled to the second terminal of the second RF circuit package such that the main RF filter path is extended between the first terminal of the first RF circuit package and the second terminal of the first RF circuit package;
• and
• a second piezoelectric substrate comprising one or more second acoustic resonators and a second main RF filter path section of the main RF filter path, the second main RF filter path section is coupled to the second terminal, wherein the first piezoelectric substrate is different than the second piezoelectric substrate.