A Lange Coupler is used to test the validity of the FDTD method and XFdtd^® in the analysis of microstrip structures. Further reading on similar structures is also available in this example.

These files show XFdtd results for a 3dB Lange coupler. Figure 1, Figure 2, and Figure 3 are views of fields in and around the device as rendered in XFdtd. A plot of the S parameters S11, S21, S31, and S41 is shown in Figure 4.

Recommended Reading:

Detailed discussions of the Lange Coupler and several other microstrip devices (including a branch line coupler, a coupled line coupler, and a Wilkinson power divider) are available in the partially reproduced Ph.D. dissertation by Jose G. Colom -  "Analysis and Development of Microstrip Interdigitated Structures Using FDTD and Statistical Techniques" 197.41 Kb