Surface Acoustic Wave (SAW) sensors across center frequencies from 100 MHz to 750 MHz were investigated for magnetic field detection based on the ΔE effect. The sensors, fabricated on 128° YX-cut LiNbO₃ with FeCoSiB as the sensitive layer, use gold IDTs to generate surface waves. Variations in IDT dimensions allowed control of the center frequency, revealing frequency-dependent sensitivity. Experimental results showed increased sensitivity at higher center frequencies, influenced by the material and structural design.