SimRF-->Circuit Envelope-->Directional Coupler Model - INCORRECT IMPLEMENTATION

I am experimenting the "Ideal Couplers - Directional coupler" under the SimRF->Circuit Envelope->Junctions toolbox. The parameters I play with are the Insertion loss and Coupling. I fixed the Coupling to 25dB and the insertion loss cannot go below 0.51dB else an error message pops up saying " Expected passive test for Directional coupler to be nonzero.". That doesn't make sense. (10^(-coupling/20))^2 + (10^(-insertion loss/20))^2 = 1. With 25dB coupling, the insertion loss can go to 0.014dB. I suspect the implementation is wrong. Anyone has any idea?

Thanks, cfy30

Answer 1

[Andreas Loeffler]

I can confirm that issue. I am using 2016a. I guess one has to construct its own directional coupler with S parameters.

Answer 2

[Joe Storniolo]

Having the same problem, and I'm using 2018a.