Inductance at High Frequencies and Its Relation to the Circuit Equations

Inductance is essentially a low-frequency concept. On the other hand, transmission line analysis based on low-frequency circuit equations can be applied to lines and even antennas carrying high-frequency currents, with approximately correct results in many cases. The problem here attacked is that of determining in what manner the term -LdI/dt, representing the self-induced electromotive force, must be modified when low-frequency circuit theory is applied to high-frequency wire circuits. The results indicate that in addition to a change in L, an entirely new term Nd²I/dt²must be introduced. The quantity ω²N, here called radiactance, has units of ohms and is intimately related to the so-called radiation resistance.