Re: clear my ie3d doubt
Hi, Bala:
1. The Highest Freq (Fmax) = 5.9 and the Cells per Wavelength (Ncells) = 40. For the same meshing density, you can change them to Fmax = 11.8 and Ncells = 20. That is the reason I just changed them to Fmax = 12 and Ncells = 20.
2. For the finite ground plane structure, I used the AEC RATIO = 0.1 and it makes the edge cell width to be 0.1968. In fact for AEC Ratio = 0.1, the center conductor is not meshed with edge cells, you may consider reduce the AEC RATIO or use multi-layer AECs.
For the infinite ground plane structure, I also use AEC RATIO = 0.1. However, the estimation program estimate the waveguide wavelength differently due to the difference in the dielectric configuraiton. The estimation of waveguide wavelength can be very accurate for multi-layer structure. Normally, you do need to change the Ncells and make sure the meshing is fine enough. For your structure, it is meshed quite fine and it should be ok.
3. When I model the slot antenna using infinite ground plane, the resonant frequency is 8 GHz and it is much higher than the 5.5 GHz predicted using the finite ground plane version. In the other word, the slot's resonance is at 8 GHz. The resonance happens in your finite ground structure is not due to the slot, it is due to the finite ground plane size. In some sense, your finite CPW ground is a very important part of your resonator.
4. In your original structure, you define an infinite ground at z = 0. Then, you define your CPW fed slot antenna on z = 3.175 mm. The CPW ground is finite.
Best regards,