Hi, I was wondering if it's possible to place a bandpass fss on an slot antenna in order to have a pec plate outside of the operating frequency band of the slot antenna.
Is it possible to place the fss right on the slot? If not what would be the physical reasons to need a minimum distance between slot and fss?
Unfortunately, I'm not sure what you mean by "in order to have a pec plate outside of the operating frequency band of the slot antenna". Can you elaborate?
In general, FSSs are designed to operate on plane-wave modes. By placing the FSS close to other objects, you'll typically excite a large number of modes on the surface, and you might not get the response you are looking for (not to mention detuning of the slot).
Thank you for your quick response. Regarding the pec plate my idea is to make the fss, which is placed between the slot edges (inside the), behave like a pec sheet for all frequencies except the operating frequency of my slot antenna i.e. an incident plane wave (approaching the slot antenna) shall show the same reflection properties as it would show on a pec plate for all frequencies except the operating frequency of the slot antenna because the fss is supposed to be 'transparent' in the operating band of the slot.
Properties such "pec sheet" and others refer to the impedance seen by a plane-wave mode. Since in the near field of a radiating body, you will have a larger set of modes, so you may see unwanted behaviors. But, your setup might still accomplish its purpose. It's hard to say for sure in the generalized sense.