On the operating mechanisms of flexible microwave inductors and capacitors under mechanical bending conditions

Flexible microwave passive components play an important role in flexible integrated circuits, especially for high-speed wireless communication systems. It is inevitable that bending condition could have significant impact on the flexible components' performance. However, analysis on the physical mechanism of the flexible microwave passive components under mechanical bending conditions were yet to investigate. In this paper, performance variations and operation mechanisms of flexible microwave inductors and capacitors under mechanical bending conditions were studied. Flexible spiral inductors and MIM capacitors with various dimensions were fabricated on plastic substrates and measured under different mechanical bending conditions. Modeling of the flexible components was conducted. The influences of mechanical bending on the flexible inductors and capacitors were characterized based on the experimental and modeling results. By extracting the distributions of the electric and magnetic fields from the model, underlying operation mechanisms of the flexible inductors and capacitors under bending conditions were discussed. In addition, the performance variations with different component parameters (e.g. metal and substrate material, thickness of the metal and dielectrics) were studied under bending conditions. The results were helpful for the employment of flexible microwave passive components towards flexible microwave monolithic integrated circuits.