Simulation of high frequency properties of planar magnetic inductors prepared by direct write techniques

High frequency characteristics of the inductance (L) and the quality factor (Q) of square spiral type planar magnetic inductors prepared by direct write techniques were simulated using a Maxwell three-dimensional field simulator. The materials, cross-section shape, thickness and conductivity of the coil were varied to estimate the trend of the inductors’ performances. The area dimension of inductors utilised was 1·3 × 1·3 mm. Al₂O₃ was used as the substrate material. The used inductors with a permalloy (Ni₈₁Fe₁₉) core, silver (Ag) coils, trapezoid shaped cross-section of 30 μm thick coil and coil conductivity of 70% of Ag bulk value exhibit L=12·3 nH, maximum Q=33 near the frequency of 50 MHz and a self-resonant frequency of 0·78 GHz. The simulated high frequency data of inductors agreed well with those obtained from the equivalent circuit model of inductors.