Naive question on quality factor

  1. Noct1
    Noct1
    Hello,

    I am in the very (very) beginning of my training in antennas and I have a naive question on antennas quality factor.
    I always thought that quality factor Q was simply a quantification of the sharpness of the resonance peak. So, if two antennas have the same quality factor, their resonance peaks would have the same sharpness.
    Yet, it appears that I was wrong.

    Since the formula is Q = f/Δf, the sharpness is only defined by the bandwidth Δf. So if two antennas have their resonance frequency at 1 GHz and 2 GHz respectively, and the same resonance sharpness, then the 2 GHz antenna would have a 2 times the Q-factor of the 1 GHz antenna.

    Am I right or do I miss something obvious ?

    I am sorry for the naive question but I am pretty confused, because I know that researchers that use waveguides to estimate the complex permittivity of materials correlate the variation of the resonance frequency with the real part of the permittivity, and Q-factor variations with the dielectric losses. If Q variations contains frequency variations then it must be more difficult than I thought.

    Thank you!
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