slotted patch antenna in HFSS

[dlock]

I am designing a double H shaped slotted patch antenna in HFSS. The two H shaped slots are perpendicular to each other. At top is the slotted patch attached to the ground plane via a feeding pin and shorting pin.The feeding pin being fed by an SMA connector attached to the ground plane.I wanted to know the following:

1. Do i need to assign perfect E n assign infinite ground plane to the ground plane structure?If so to which face of ground plane should i assign these,upper or lower one?

 

[roxxon]

The infinite ground plane is for purely theoretical stuff only - I only use it to show people the "perfect" monopole pattern.

Since in the end you probably want to build and test the antenna, I'd strongly suggest you assign PerfE to your ground plane - because the size of it has a big impact on the whole behavior.

Of course, if you use sheets (instead of solid boxes), then also the patch is PerfE. The pins should be PEC (at least for first impressions, to minimize computational time). Normally the SMA connectors are built of two cylinders (the inner is the pin, therefore PEC, the outer is the isolation, normally Teflon, eps=2.1) where the lateral surface of the outer cylinder is also PerfE.

Hope that helps. Otherwise some more clarification on your problem would be nice.

 

[electricMac]

Hello people!

I'm trying to create a probe feed cylindrical slotted patch antenna with a shorting pin & supertstrate, so I have a few questions:

1)does the shorting pin (and the coax) have to touch only ground plane and patch? My question is more about the patch, because my design has 7 slots, so there are not many available positions for the pin and coax.
2)does the size of shorting pin and coax (their radii) play a significant role as far as the resonant frequency is concerned?
3)which could be a good position for the shorting pin and coax in such a design? E.g: both of them above the first slot or pin above the first slot and coax between the first and the second...

I'm quite new at this, so I really need your help!!!
Thanks in advance,
Mac

 

[roxxon]

1) What do you mean with that question? Of course the shorting pin has to touch the ground plane and the patch -- but what else is there to touch?

2) Yes, especially the size of the shorting pin does play an important role, because its inductance is a function of its thickness. The same goes for the coax pin -- but that size is generally given by the connector to be used in the end, anyway. So, just use that diameter.

3) The actual position of course is highly dependent on your design and what you actually want to accomplish... so there is, where the engineering really starts...

 

[electricMac]

Thank you Roxxon for the answers!

About the first question: the circular face of the pin that touches the patch, is it possible to "touch" a slot? Not the whole face, but a part of it.

So how do i pick the radius of the shorting pin if i know the resonant frequency that i want to accomplish? I already use a specific coaxial cable (50 Ohm) that is realistic (can be found on the market), so i am interested mainly about the shorting pin (material: pec)
Is there any papers or e-books that have details about shorting pins?