36.1 Matched X-band magic T coupler

This example is available in .../QW-3D/Standard/PassiveComponents/MagicT/magict_matched.QWPro in the QW-Modeller examples directory and can be loaded using File®Open Examples... command from main menu.

General Description

The structure is a model of X-band magic T (or magic tee or hybrid tee) coupler with matching elements. Matching rod and iris are visible inside the junction.

Geometry

The magic T consists of four rectangular waveguides (WR90 22.86 x 10.16 mm) meeting in a single junction. To minimise return losses of magic T arms, matching post and iris are placed inside the junction. The ports are located inside the arms, behind the flanges. The mesh is limited to active areas only (flanges are not included) to make scenario as compact as possible.

The ports for S-parameters extraction are numbered as follows:

[1] – input port,

[2] – output (transmitted) port,

[3] - coupled port

[4] – isolated port

Post Processing

Full S-matrix is calculated with Smn postprocessing. S-parameters are presented in the frequency band from 8 to 12 GHz.

Return loss for each port. With matching elements (left) and without matching elements (right).

Scattering parameters for excitation from port [1].

In the frequency band 9-11GHz, transmission to arm E (port [4]) and arm H (port [3]) is close to -3dB. It can be noticed that the collinear port [2] is isolated.