Ultrasound :

"Ultrasound is sound with frequencies greater than 20 KHz. This frequency is the
approximate upper audible limit of human hearing in healthy young adults. ……
Ultrasonic devices operate with frequencies from 20 KHz up to several GHz."   ......... Wikipedia

Vibration :

Ultrasound can propagate energy through a medium (air, water, or any touchable
object) via mechanical vibrations. The method of generating these vibrations
involves applying an electrical signal with an ultrasonic frequency to a piezoelectric
ceramic element (PZT), causing it to vibrate.  This vibration is then transmitted
through tightly bonded metal elements. 

Ultrasonic transducer:

By enclosing the PZT within a tightly bonded metal casing, electrical energy is
converted into mechanical energy.

Factors affecting the efficiency of ultrasound applications:

  (1) Driven Architecture

        The control signal for driving ultrasonic waves generally employs two types
        of architectures:self-oscillating and externally driven.  Among these, the
        externally driven architecture, particularly the full bridge drive, is known for
        its highest efficiency.

  (2) Resonance frequency

        The resonance frequency is the most crucial factor affecting efficiency. 
        Ultrasonic devices must operate at their resonance frequency, as
        working outside this frequency severely diminishes efficiency.

Full Bridge externally driven Architecture

  . Sine wave output least harmonic noise maximum efficiency

  . Precise frequency setting allowing for high accuracy

  . Fixed output after frequency scanning, 25% to 35% efficiency 
    gains beyond existing solutions

  . Purely hardware based design, ensuring rapid response time

  . built in protection features, ensure system safety

BiTEK offers full bridge architecture, dedicated IC, optimal solution for ultrasonic applications.

Resonance frequency:

“Resonance describes the phenomenon of increased amplitude that occurs when
the frequency of an applied periodic force (or a Fourier component of it) is equal or
close to a natural frequency of the system on which it acts. …… Resonance occurs
when a system is able to store and easily transfer energy between two or more
different storage modes.”                                                                         ......... Wikipedia

   Operating the ultrasonic frequency within the resonance range (BW)
                                  results in the highest efficiency for ultrasonic applications.

How to find the resonance frequency:

(1) Control frequency with externally driven architecture.
(2) Locate resonance frequency by scan the operating frequency.

Frequency scanning solution: (partial)

Driving Ultrasonic device with Full Bridge/ External Driven architecture to control Transducer operating within Resonance Frequency Range