I am designing a multilayer antenna. The top layer is radiator, second layer is substrate, third layer is meshed metal ground, forth layer is another substrate, and the bottom is feeding network.
That's to say the microstrip antenna and its feeding network share the same ground in the milddle.
When I put one more layer of substrate over the radiator, everything shift down. When I adjust the profile of the radiator to shift them back to normal, a mismatch point appear in my band.
So, can anyone tell me how to match it. Or how to introduce a parasitic resonance at the unmatched point to lower the S11.
Biz