Inductance of planar rectangular-spiral strip conductors for low-profile inductors

Two methods are presented for calculating the inductance of planar rectangular spirals. The first method assumes current flows only in the exact center of the conductor. The second method is based on uniform current distribution across the conductor width, and results in significant improvements in the calculated value of the inductance. The effect of introducing a magnetic core is also studied. The calculated values of inductance from both methods are compared with laboratory measurements, and the accuracy of the methods is demonstrated