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/sub 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/sub f0/. When the dimensions of Fig. 1(a) and (b) are such that s' = s, it is convenient to denote the difference between C/sub f0'/ and C/sub f0'/ by /spl utri/C/sub f0/, and define it as the interaction between the symmetrical odd-mode fringing capacitances. Clearly, /spl utri/C/sub f0/ has the property of approaching zero as w/ (b - t) /spl rarr/ 0 [w is defied in Fig. 1(a)]. Moreover, whenever /spl utri/C/sub f0/ is known, C/fub f0/ is also known.