Create a regular mesh in "concentric" circle

Hi everyone,

I am trying to recreate the mesh that you can see in the attached image (imm_1). 

How is it possible to define a regular mesh in this type of geometry? I can manage one circle inside the other but not more.

Second question: How can i manage a surface among three circle curve? I tried using loft and boundary surface but doesn't work. In attached my last attempt (imm_2). 

Do you have some suggestions?

Thank you so much

Best,

Andrea