ultrasonic microphone membrane replacement?

[coppercone2]

I have a ultrasonic microphone that I had to repair and I lost the membrane the small SMD mic was glued to 

It looked like some kind of fabric, kind of like thin 'tea cozie' or something. It would be suitable for maybe one of those semi see through window curtains, the white lacey ones, the material was too stiff for clothing... maybe it would be suitable for those cloth 'pauldrons' that rich people used to wear in like the 1500's.

Any ideas? Bandwidth is 100KHz. I don't mean the black foam diffuser thing, the microphone is basically a aluminum tube with a connector on the end with a SMD part glued to a membrane on the top that the microphone diffuser sits on. I need that membrane.