What is Phase Balance and Amplitude Balance in a Balun?

Phase balance and amplitude balance are a measure of how accurately the signal power and phase (180° out-of-phase) are matched between the two balanced (differential) ports of a balun. Phase balance is given as the measurement in degrees of the difference in phase between the inverted output from the non-inverted output. Baluns with a phase balance closer to 0° are higher performing baluns. Amplitude match is a measure of the match of the output power magnitude between the two balanced ports. An Amplitude match closer to 0 dB is an indicator of a higher performance balun.