how to increase piezo power handling


How do I increase the power handling of the ksn 1038 without changing
the overall efficiency?
If I put 2 of them in parallel, the overall efficiency will go up by
6 db. If I put 2 of them is series, the overall efficiency will
not change correct? Because doubling the impedance decrease the
efficiency by 3db, and doubling the radiating area increase it by
3db so net gain is 0. However these piezos act like capacitors at
hight frequency that is why you can use them without a filter
capacitor, but would putting 2 of them in series result in 1/2
the capacitance at high frequency and therefore shifting the xover
frequency upward?



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