disadvantage of pcb

Hi

what will be the disadvantage of using a PCB substrate for patch Antenna design?
compared to that of using sheet metal parts for the same?

If we use PCB for Microstrip antennas, whether it will have performance degradation over the time period?

regards

Karthik

There isn't any disadvantage for using (as example) a standard FR4 substrate for
microwave range antenna design.
We haven't comparatively measurements, but PCB antennas made 2o years ago on FR4 at 9.6Ghz are working ok now. I think only the harsh environements could really destroy performances (rain, sun, etc and wrong antena packaged designs).

Hi
PCB substrate has a low di-electric constant. So we have to make larger structures (patches) on them.

If we use dedicated substrates with high di-electric const we can reduce the size of the patch. And degradation will depend on the quality of the PCB material.

thanks for ur replies........