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HMC773LC3B - Coupling with PA (HMC6981)

Question asked by estoll on Jan 22, 2016
Latest reply on Feb 10, 2016 by SMcBride



I am working with RF front end PCB with the HMC773LC3B used for the upconverter on the Tx chain and downconverter on the Rx chain.  The Tx chanin uses the HMC6981 for the power amplifier and is outputing +32dBm at 16GHz.  I am observing that the PA is radiating 16GHz from it's package and the HMC773LC3B is absorbing the the 16GHz which is getting downmixed to an IF.


My first prototype used eval boards with the mixers and PA separated by a farther distance than on my PCB design.  I can replicate the coupling that I am seeing by moving the HMC773 mixer and eval boards closer together.


Does anyone have recomendations on design guidlines with these components or possible replacements for either the PA or the mixer?  Does the new HMC773A have better performance?  It seems that I could solve this issue with either a PA that radiates less or a mixer that will absorb less.


Thank you