Tuning Range Comparison Between Different Planar Inductors Layouts on PCB

This paper aims at comparing the tuning range of three different planar inductor layouts built on a Printed Circuit Boards (PCB), namely the spiral inductor, the nonspiral inductor, and the meander inductor. Initially, we identify the equivalent electric model for the three inductors. All models are validated theoretically by analytical equations, by simulation through Sonnet software
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, and also by measurements. For the same surface occupancy, the spiral inductor presents the higher inductance value, while the nonspiral inductor has the higher quality factor and self-resonant frequency. The tunability range is investigated by placing a shielding metal plate above for all PCB inductors. The inductance value is reduced, when the air gap between the metal plate and the inductance decreases. In addition, results demonstrated that the spiral inductor has the higher range, with a variation of more than 90%, followed by the non-spiral inductor. The meander one showed a change less than one-tenth of the spiral inductor.