Observations on computational outcomes for the characteristic modes of dielectric objects

Some computational aspects for the characteristic modes (CM) of dielectric objects are examined. Volume integral equation (VIE) formulations are reliable but computationally burdensome. The use of surface integral equation (SIE) formulations results in a lighter computational load but, we show here, obtrudes certain non-physical modes in addition to the physical ones. We show that the non-physical ones are easily identified using a radiated power check, and can be discarded, so allowing use of the SIE for finding the true CMs of dielectric objects. The SIE can be used with fine meshing with relatively modest computational resources; this is of practical importance.