The fundamental difference between power splitters and power dividers (combiners) is the resistor configuration used to separate the power.

Power dividers, which use three 16 ²/₃ Ω resistors, are built for direct power dividing applications where it is necessary to split one source into two parts for separate measurements. For leveling and ratio measurement applications, where power is sampled from one arm, the three-resistor configuration of the power divider causes poor source match, resulting in significant ripple in the calibration or reference trace. Point “A” in the diagrams below is held constant by the leveling action and looks like a source with zero impedance. The auxiliary arm output impedance is equal to the resistor value of the arm. Using the three-resistor divider results in a 16 ²/₃ Ω output or a 3:l VSWR mismatch, which contributes significantly to measurement uncertainty. The two-resistor configuration of the 11667A and 11667B provides a 50 Ω output impedance to minimize uncertainty in these applications.

The following is an overview of the main parameters of the power splitters and power dividers. This overview is extracted from the paper of R. A. Johnson, “Understanding Microwave Power Splitters,” Microwave Journal, December 1975.

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