Thank you Damian,
I made what you told for the structure, but from my knowledge that the PBG was drawn before building the structure to discriminate the gap and pass windows.
Another thing when i build the structure as shown in the attached paper one figure confirmed and the other not. I am attached the structure after build it. For my application I want to let one input exist (high) and the other (low)!!!!!
please help me to do this.
Thanks again for your reply,
Tamer