Best substrate materiall for 20 Ghz

Hii frens, I want to know that which substrate material would be best for high frequency application like for 20 GHz...

Thank you

High Frequency Laminates

I used RO4350B 10mil 1/2oz up to 23GHz.

Alumina with TiW/Au (awesome, but SSSSS)

For more cost-effective materials, look into Rogers Corp High Freq Laminates, as vfone suggested.

Thnk You..
But which series of Rogers material would be most suitable...?

rogers 5880 & 5890

Start with the suggestions on this forum, but I'd also recommend that you read the vendor spec sheets for those materials and learn what aspects make them suitable for operation at these frequencies. Even a simple phone call/e-mail to one of Rogers' technical people could be an enlightening experience.