-----Original Message-----
From: Steve Kelly [mailto:[log in to unmask]]
Sent: Friday, January 24, 2003 12:09 PM
To: IPC ([log in to unmask])
Subject: HI - SPEED NOISE PROBLEM

 

Dear Technetters:

 

I have a question about noise levels at high speed on a flex circuit. The circuit is:

1) surface microstrip design  (.004 tracks on one side – x- hatched ground plane on other)

2) impedance is approx. 50 ohms

3) construction is:   .0005 kapton

                             .0005 adhesive

                             .0007 RA copper )

                             .002 kapton        ) DuPONT AP

                             .0007 RA copper )

                             .0005 adhesive

                             .0005 kapton

4) part is pad plated/selective plated

5) finish is immersion gold over electroless nickel

6) circuit is less than .5 inches long

 

When we measure the S parameters of the 50 ohm trace, the bandwidth starts dropping at 6 GHZ , peaks at 13 GHZ and then drops –  I have a pdf. file which I can send off-line or post it to somewhere?

 

Any thoughts?

 

Thanks

Steve Kelly

 

PFC Flexible Circuits Limited