New types of TLM nodes for the analysis of axially symmetric structures

The Transmission Line Matrix (TLM) method is a well-known numerical time-domain technique which has been widely used for solving electromagnetic field problems. Axially symmetric structures are frequently encountered in microwave engineering. For this purpose, a first memory-saving TLM algorithm was developed in the particular case of uniform guiding structures [1]. Based on the classical Symmetrical Condensed Node (SCN) [2], this approach leads to a 1D mesh array using 18 complex voltages. Low memory requirement and simple algorithm make this method a very versatile tool. Extension of this model to general axially symmetric structure (2D mesh array) is not memory competitive compared to other time domain methods as BoR-FDTD [3,4].