A hybrid coupler is a directional coupler that is designed to split power equally among two ports. They are most frequently created from two coupled transmission lines that are set near enough together that energy which passes through one is coupled to the other.
Hybrid couplers come in two types: 90 degree hybrids (also known as quadrature hybrids) and 180 degree hybrids. But what is the difference between the two?
90 Degree Hybrid Couplers
90 degree hybrid couplers are four-port devices that are used to either equally split input signals with a 90 degree phase shift among output ports or to mix two signals while upholding high isolation between the ports.
When power is received at the IN port, half of the power travels to the zero degree port while the other half is coupled to the 90 degree port. Any reflections from mismatches that are sent back to the …