ANALYSIS AND OPTIMIZATION OF PLANAR THICK FILM NI‐FERRITE INDUCTOR

Ni‐ferrite powder average grain size less than 0.9µm was used for the ferrite paste preparation. Ferrite paste was printed on Al2O3 substrate and fired 850°C/10min. After Ni‐ferrite thick film characterization had been done, simple planar inductor geometry, such as square spirals, were printed on it. Measurements were done, using an HP 4194A impedance analyser. The experimental results were summarized and compared with theoretical predictions given by the electromagnetic analysis using the method of current images for the reason of accounting the effect of magnetic substrate. The computer program, developed here, allows determination of the required thickness of the substrate which will produce inductance enhancement of the given permeability of the substrate material. The same results can also be used to determine the permeability of magnetic film or substrate quickly and are directly applicable to the design of the planar inductors.