Filter module with enhanced temperature ruggedness in smaller size

A radio frequency module comprising:

• a packaging substrate configured to receive a plurality of components;
• and
• a filter module implemented on the packaging substrate, the filter module including a first terminal, a second terminal, and a filter disposed along each signal path extending from the first terminal to the second terminal, the filter including a plurality of series resonators and a plurality of shunt resonators disposed between the series resonators and a ground, at least one resonator among the plurality of series resonators and the plurality of shunt resonators being a first type of resonator with a temperature compensating layer, at least one resonator among the plurality of series resonators and the plurality of shunt resonators being a second type of resonator without a temperature compensating layer, the at least one of the plurality of series resonators and the plurality of shunt resonators being the first type of resonator being disposed between shunt resonators of the second type and being a shunt resonator most responsible for raising a skirt steepness or a channel insertion loss of the filter.

A mobile device comprising:

• an antenna configured to receive a radio frequency signal;
• and
• a front end system configured to communicate with the antenna, the front end system including a filter module including a first terminal, a second terminal, and a filter disposed along each signal path extending from the first terminal to the second terminal, the filter including a plurality of series resonators and a plurality of shunt resonators disposed between the series resonators and a ground, at least one resonator among the plurality of series resonators and the plurality of shunt resonators being a first type of resonator with a temperature compensating layer, at least one resonator among the plurality of series resonators and the plurality of shunt resonators being a second type of resonator without a temperature compensating layer, the at least one of the plurality of series resonators and the plurality of shunt resonators being the first type of resonator being disposed between shunt resonators of the second type and being a shunt resonator most responsible for raising a skirt steepness or a channel insertion loss of the filter.