Double-stub tuner possible structures

Hi all!

Is it possible to build a doble-stub tuner using one of these combinations: (serial stub + shunt stub) or (serial stub + serial stub)?

Thanks in advance.

It depends on range of matching, although I don't know what you want to mean by "serial stub + serial stub".

Normally, the double stub impedance matching network uses two shunt or parallel stubs, I would like to know if there are another structures which use a parallel stub and another serial stub, instead of two parallel stubs or a structure that uses two serial stubs instead of two parallel ones.

In many textbooks only appears the double stub tuner with two stubs in parallel and I want to know if there are another types of structures to match the system.

I mean the second configuration in the image attached.

What mode do you intend to drive for (b) ?

Both single-ended and dofferential modes are valid for (a).

Consider microstrip line or coaxial cable.
How to implement (b) for them ?

Sorry, I will try to make a better question: Can the attached structure work as an impedance matching network and to be useful?

Mathematically, it can work.
However it can not work as actual implement especially for high frequency.

Maybe it can work for low frequency with parallel feeder line.

Then, I imagine that your reasoning will be the same for the configuration attached.

Mathematically, it can work, but only for low frequency, can't it?

One more thing, what would be the problem of these structures at high frequencies?

Yes.

(1) We can not realize this by single-ended-line such as microstrip line or coaxial line.

(2) Even if we use differential line which have even and odd modes, very large reflection will occur at "serial? stub".
Consider behavior of modes at "serial? stub".

there ARE double slug tuners, where a capacitance is placed across a line, and is allowed to move in position. So i guess you COULD have a single stub tuner, that joins the main line capacitively, and can slide its position along the main line too. that would be a little like a series/shunt tuner.