Hi,

I am not very much sure, if you are getting S11 less than -10dB at 2.4 GHz, then it should be okay, but check VSWR accordingly for that.

As you are raising a query about axial ratio " truncation t / W, as well as vertical height of the ground plane, is the axial ratio and likewise the ground plane size controls the gain of the antenna while the distance between ground plane and the patch affects the

bandwidth, whereas the size of the feed gap influences the impedance matching".

So axial ratio should be less than 3 dB, but ofcourse, axial ratio decreases with frequency and then suddenly it will start increasing with frequency. You can go for array of patch (double patch) deciding wavelength between them. you will get more accurate results.

Thanks,

Hi,

You should get both at the same frequencies. To have both at the same frequency fine tune any one dimension (length, width, feed position etc.) of the antenna. Also, try varying the slot dimensions to match the frequencies.

Hello,

getting circular polarization means; you need to get two orthogonal modes whose frequencies are very close to each other.  The frequency corresponding to minimum s11 and minimum axial ratio will be different. it is equivalent to connecting two parallel LC circuits in series.