The quality factor QZ of the combined TE10 / TM10 spherical mode

This contribution describes an evaluation of the quality factor Q_Z of the combined TE₁₀ / TM₁₀ mode, including the internal and the external region of the bounding sphere. The proposed method uses a potential definition of complex power, implicitly avoiding infinite entire space integration. It is shown that Q_Z of the combined mode is not (unlike classical Q) limited to one half of the value for the pure TM₁₀ mode. It is shown that the Q_Z factor does not have a strict lower bound other than zero.