Free Wilkinson Power Divider Tool
Calculate equal and unequal Wilkinson power splitters, quarter-wave branch impedances ($Z_{02}, Z_{03}$), isolation resistor $R_{iso}$, and microstrip trace geometry.
📡 RF Design & Split Specifications
📊 Divider Transmission Lines & Resistor
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Theory of the Wilkinson Power Divider
Invented in 1960 by Ernest Wilkinson, this passive network splits an input RF signal into two in-phase signals with matched impedance at all ports and high isolation between the output ports.
Even-Odd Mode Analysis Equations
For an arbitrary power division ratio (k^2 = P_2 / P_3):
$$Z_{02} = Z_0 sqrt{ rac{1 + k^2}{k^3}}$$
$$Z_{03} = Z_0 sqrt{k(1 + k^2)}$$
$$R_{iso} = Z_0 left( k + rac{1}{k} ight)$$
For the classic equal 3 dB splitter ((k=1)), these reduce to (Z_{quarter} = sqrt{2} cdot Z_0 = 70.71Omega) and (R_{iso} = 2 Z_0 = 100Omega).
Frequently Asked Questions
Why does no power dissipate in the isolation resistor during matched operation?
When driven from Port 1 into matched loads, identical voltage waves reach Ports 2 and 3 with zero phase or amplitude difference. With zero voltage differential across the resistor, zero current flows and zero power is lost.
What package size should be used for the isolation resistor?
At microwave frequencies above 1 GHz, minimize parasitic inductance by using compact 0402 or 0603 SMD chip resistors.