Conventional Microstrip to SIW Tapered transition- clarity

Hi,

In substrate wave guide (SIW) transitions, Conventional Microstrip to SIW Tapered transition is used widely.

1. What is the role of TAPER structure here?

2. What is the impact of taper length ?

3. Which parameter of this tapered transition does Impedance matching ? plz explain in detail.

4. Which parameter of this tapered transition does mode matching (QUASI TEM to TEM) ? plz explain in detail.

1. it should provide a good matching over the complete SIW bandwidth.
2. The taper length is generally chosen to be a multiple of quarter wavelength, so that the return loss is minimal.

Hello, you might want to see (and try to redo) this paper, is very important, you will find the answars of your questions ,, Good luck
(paper title : Improvement for the design equations for tapered Microstrip-to-Substrate Integrated Waveguide transitions )
http://ieeexplore.ieee.org/document/...8/?reload=true