A Lower Limit on the Interaction Between Symmetrical Odd-Mode Fringing Capacitances (Letters)

Let us denote the familiar odd-mode fringing capacitance which is plotted in graphs given by Getsinger by C_f0. It is further defined by Fig. 1(b) in the limit as the magnetic wall tends to infinity on the right. We also denote the corresponding fringing capacitance of the symmetrical coaxial structure of Fig. 1(a) by C_f0. When the dimensions of Fig. 1(a) and (b) are such that s´ = s, it is convenient to denote the difference between C_f0´ and C_f0´ by ▵C_f0, and define it as the interaction between the symmetrical odd-mode fringing capacitances. Clearly, ▵C_f0 has the property of approaching zero as w/ (b - t) → 0 [w is defied in Fig. 1(a)]. Moreover, whenever ▵C_f0 is known, C/fub f0/ is also known.