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Probe(coax) fed antenna in Momentum

Question asked by S_RAHMAN24 on Dec 4, 2006
Latest reply on Dec 13, 2006 by ALEPEREZ
Hi,
I have read the previous discussion of probe fed antenna( Probe Fed Antenna How?« on: December 1st, 2003, 2:33pm »)

But still I've got some confusion.

The antenna I am going to simulate has 2 substrates.The patch is on FR4 which is suspended over the ground plane with an air gap of 25mm. The susbtrate definition look like:
Freespace
--------- strip cond  (my patch)
FR4(1.6 mm)
---------
Air( 25 mm)
////GND//////


Now my antenna should be fed by a probe(coax). So I need to connect a coax whose outer conductor will connect to ground and the inner conductor will extend through the air, FR4 to the patch(soldered). Now in momentum I know that I can make a via in some layer and then map it in substrates. but my question is, where should I connect my port for simualtion. As my port is the source of electrical excitation, physically it should be somewhere on the patch surface. I made a via there and drew a circle in some layout(e.g. "res"). But should I connect my port to the patch layer(an internal port) in that point( where the center of the circle(via) is, as this should be the physical position of inner conductor of coax through which the patch will get power)? OR I should connect the port anywhere?  

I tried the second solution of the previous discussion ( making another conduction layer and connect port to that) still confused about the position of the port.
I didnt understand the first solution which talks about some slot /hole.

SORRY for long post. Can anyone help? My main concern is where to connect the port while I am using a via to express coax.

Thank you very much.  

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