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Configuration

The matching system is shown in Figurę 3.9. For the reasons described in a later paragraph

we are working in admittance terms.

At the right of the diagram is shown is shown a load admittance Yi. A linę of characteristic admittance Yoand length I connects the load to a junction point between

the main linę and a short circuited stub linę of which the characteristic admittance is also

Yo. To the left of that junction, i.e. at the reference piane D, a transmission linę whose characteristic impedance is also assumed to be Yois supposed to be matched, i.e a wave

propagating to the right in that linę is not reflected when it reaches the junction. This will be because, when we have correctly designed the matching system, the admittance of

the parallel combination of the admittance provided by the stub linę and the admittance

at the reference piane C is equal to the characteristic admittance Yo of the linę at the reference piane D to the left of the junction.

In the design of this matching system, the lengths s and I are the variables to be found. Because the stub is connected in parallel, we work in admittances, which combine

in a simple way (they simply add) for parallel connections.