MMIC Layout problems with bad return loss and gain

I have a MMIC Amplifier (2-18GHz HMC463) from hittite.
I have designed a borad for this componenet
but only I could get performance up to 12 GHz. at upper frequencies the return loss an gain was very bad.
What can I do? have any boy a layot files of Hittite? ar any useful thing?

Hi, What kind of PCB material do you use ?.

Paul.

The quality and the placement of the bypass capacitors are very important for this circuit to get a flat response up to 20GHz.

the performnace depends on the housing and the types of capacitors, indutors and resistirs u r using. Try to check teh feedback loops

I have used a taconic board with er=9.5, loss tangant= .0035, H=25 mil
I have used a CPWG feed structure similar to figure of evaluation board in datasheet.
I simulated the feed with ADS. and was matched
Width of MMIC input port is .3 mm. I used a CPWG to reduce width of 50 ohm line.
This MMIC has internal DC block and RF choke, So this phenomena has another resoan.
have you any idea?