ANtenna's 2nd harmonic yields a better S11 than its centre f

Hi all,

i did some S-parameter meaurements my patch antenna designed at 1.5GHz. What is that the 2nd harmonic produce by the patch antenna yields a better return lose,S11 than the centre frequency at my targeted 1.5GHz?

Is there anyway, to overcome the 2nd harmonic? Or is there any explanation to the better return lose than the centre frequency? Thanks!

That is not a significant fact, other than to tell you that your impedance coupling point to the patch antenna is in the wrong place. Try moving the coupling point closer or farther from the center until the antenna is matched at the fundamental frequency.

Okie roger that! Thanks