Hi List,

I recently sent away a surface mount PCB for manufacturing quotation.  The
head engineer there sent it back saying I shouldn't run large tracks through
chip capacitor pads as they will suck away heat and lead to component
tombstoning.  My problem however is that the large tracks I am referring to
are microstrip lines carrying RF signals.  The thickness was calculated to
give a 50 ohm impedance to the frequencies of interest.  Can I just neck
down these tracks at the pads to avoid the potential problems identified by
the manufacturer or will this significantly alter the transmission line
impedance?  Has anyone come across this problem before and even better can
anyone suggest a solution.  Thanks in advance.

Regards,
Damien Cahill.

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