In power electronic based energy conversion, the high-frequency transformer (HFT) is usually excited with a high-frequency (HF) square wave voltage generated from a power electronic converter circuit (PEC). A PEC needs a reasonable dead-band (DB) and the inclusion of the DB changes the shape of the square wave. In this paper, for the characterization of the core, the DB is varied to produce different non-sinusoidal excitation voltages and an optimized excitation voltage is identified. The effect of the DB on the hysteresis loop of the HFT is also demonstrated. The mathematical analysis shows that the inclusion of the DB causes the core loss to decrease for a fixed excitation voltage and frequency. However, an increased DB produces a higher distortion at the output voltage and the current of HFT. Therefore, an optimized DB is mandatory to minimize the core loss and the distortion at the same time. Additionally, the specific loss scenario of the core under the HF triangular and trapezoidal wave voltage excitation is investigated. To validate the findings, an optimized core is simulated in COMSOL Multiphysics software and a prototype core is developed in the laboratory using the amorphous magnetic material.