Re: [Newbie Pls Help!] Difference in Resonant Frequency Measured in S11 and Imped Plo
In default, the minimum on the S11 plot indicates the best matching point with respect to 50 ohms. Note that S11=20*log10|(Z-50)/(Z+50)|, so S11 is a function of both the imaginary part and the real part of the antenna impedance. On the other hand, the resonance freq determined according to imag(Z)=0 has nothing to do with real(Z). Therefore it is reasonable to see some discrepancy between the resonance frequency found on the S11 plot and that determined based on imag(Z)=0.