Geometry of the structure
Java Wire-Frame model
Virtual reality model: you can walk into the structure!! (best seen with Live3D plugin for Netscape)
The analysis of the TE10-toTE01 mode launcher(See Fig.) has been performed with the TLM method.
For the TLM analysis the structure has been segmented into 3 blocks. Each block was discretized by an individual mesh. The meshes are - Input waveguide section. - Main cavity with the post. - Output waveguide section.
The mesh grading was such that an integer number of nodes filled the different regions. The three meshes (for the three main sections of the structure) are connected at the E-step interfaces, where they have identical cell sizes. Three additional meshes have also been used, two to calculate the modal Johns matrices (ABC purposes) and one to act as a reference structure for the input waveform.
The waveguide sections were terminated at the input and output planes by means of modal ABCs (modes up to 5_3 included, length 2,000 time steps). The S-parameters are computed after the extraction of the dominant mode from the input and output planes. The simulation was run for 50,000 time steps.
Mesh sizes, memory and CPU time required are summarized in the following table.
Mesh Size | CPU Time HP 375 | Total Memory |
~105.000 cells | 15.5 hours | 14.5 Mbytes |
Results for the S-parameters are shown(See Fig.), compared with the results obtained using a mode-matching technique [1].
[1] R. Ihmels, F. Arndt, "Field Theory of L-Shaped Iris Coupled Mode Launchers and Dual-Mode Filters" MTT-S Digest 1993, p. 765-768.
G. Tardioli, L. Cascio, M. Righi. March 5, 1997
