In recent years, there has been a growing interest in lead-free piezoelectric materials as a possible replacement for lead-based materials like PZT. Currently, the lead-free ceramic family has the most promising piezoelectric characteristics. The recently found ceramics made of potassium niobate (KNbO3) are attracting increasing attention since they could replace lead-based materials in general and be useful in medical applications. They have electromechanical characteristics that are similar to lead-based ceramics, especially undoped PZT. The state-of-the-art KNbO3 thin film bulk acoustic wave resonator is designed and simulated in this work. Ferroelectric TFBAR results show a quality factor of 1750 at a resonant frequency of 5.65 GHz. An attempt is made to decide on a perhaps strong candidate.