FIG. 5 is a diagram illustrating yet another example of a resonance apparatus 500 including a loss compensation layer 509 and a reflective layer 504. According to FIG. 5, the resonance apparatus 500 includes a substrate 501, a lower electrode 502, the reflective layer 504, a piezoelectric layer 505, an upper electrode 506, conductive layers 507 and 508, a loss compensation layer 509, and a loss compensation conductive layer 510. A cavity 503 is formed between the lower electrode 502 and the substrate 501 (or the reflective layer 504).

The resonance apparatus 500 includes the loss compensation layer 509 and the loss compensation conductive layer 510 in addition to the elements of the resonance apparatus 400 of FIG. 4. Therefore, the same elements as in the resonance apparatus 400 of FIG. 4 will not be described again with reference to FIG. 5 for conciseness.

The loss compensation layer 509 is formed on the upper electrode 506. For example, the loss compensation layer 509 may be formed by patterning an upper edge of the upper electrode 506 into a donut shape, or etching a donut-shaped trench in the upper electrode 506. In another example, the loss compensation layer 509 may be formed by vapor depositing a material including Mo, Ru, Au, silicon dioxide (SiO₂), and/or silicon nitride (SiN), on an upper portion of the upper electrode 506, and then patterning an upper edge of the material into a donut shape.