isolation in magic tee

[electroboy]

In a magic tee, if port 1&2 are collinear arms and port 3 is E arm and port 4 is H arm............ how will be the isolation between port 1 & 2 when compared to isolation between port 3&4 ? whether greater or lesser or equal..... please help
thanks in advance...

 

[bukhari917]

I am looking for the similar answer. Anyone around please?

 

[tony_lth]

can you paste a picture?

 

[bukhari917]

Here it is.**broken link removed**

 

[pstuckey]

For an ideal case these will be the same, and the isolation will only be determined by the quality of the external match.

For instance, if you feed 1 and 2, you expect to see sum and difference at 3 and 4. If loads connected to 3 and 4 have finite return loss then some of the signal will get reflected back into the magic tee and show up at 1 and 2. The paper below shows how to calculate the isolation for this case (see table 3). However, there are many ways of implementing a magic tee in practice, and unintended coupling paths between circuit elements may decrease this isolation.