Hybrid Couplers

The 3 dB hybrid coupler is a passive device wherein any in-band input signal applied to the input port will divide equally to the two opposite output ports with the adjacent port isolated. The voltage at the output ports are in-phase and 90 degree lagging phase respectively (I and Q outputs) as referenced to the input. External output terminations generally allow higher power handling than a Wilkinson power divider. Output amplitude balance is generally more frequency dependent than through a divider.