Stacked acoustic wave device assembly

A radio frequency module comprising:

• a radio frequency circuit element;
• a first acoustic wave device coupled to the radio frequency circuit element, the first acoustic wave device including a first solid acoustic mirror over a first substrate, the first solid acoustic mirror having low impedance layers alternating with high impedance layers, with the high impedance layers having a higher impedance than the low impedance layers, a first piezoelectric layer over the first solid acoustic mirror, and a first interdigital transducer electrode in contact with the first piezoelectric layer;
• a spacer assembly over the first acoustic wave device;
• and
• a second acoustic wave device having a second piezoelectric layer over the spacer assembly, a second transducer electrode in contact with the second piezoelectric layer, a second solid acoustic mirror over the second piezoelectric layer, and a second substrate over the second solid acoustic mirror.

A wireless communication device comprising:

• a first acoustic wave device including a first solid acoustic mirror over a first substrate, the first solid acoustic mirror having low impedance layers alternating with high impedance layers, with the high impedance layers having a higher impedance than the low impedance layers, a first piezoelectric layer over the first solid acoustic mirror, and a first interdigital transducer electrode in contact with the first piezoelectric layer;
• a spacer assembly over the first acoustic wave device;
• a second acoustic wave device including a second piezoelectric layer over the spacer assembly, a second transducer electrode in contact with the second piezoelectric layer, a second solid acoustic mirror over the second piezoelectric layer, and a second substrate over the second solid acoustic mirror;
• an antenna coupled to the first acoustic wave device and the second acoustic wave device;
• a radio frequency amplifier coupled to the first acoustic wave device and configured to amplify a radio frequency signal;
• and
• a transceiver in communication with the radio frequency amplifier, the first acoustic wave device and the second acoustic wave device being stacked with a spacer assembly therebetween such that a cavity is formed between the first acoustic wave device and the second acoustic wave device.