MMIC Layout problems with bad return loss and gain

[has_ajam]

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?

 

[PaulHolland]

Re: MMIC Layout help!

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

Paul.

 

[vfone]

Re: MMIC Layout help!

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

 

[akedar]

Re: MMIC Layout help!

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

 

[has_ajam]

Re: MMIC Layout help!

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?