Couplers and splitters

Revised January 29, 2010

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Welcome to the very best collection of knowledge on microwave couplers and splitters on the web!

Check out our unequal-split power divider calculator. It will design an unequal-split Wilkinson for you in a few seconds!

Power splitters and couplers are passive microwave components used for distributing or combining microwave signals. A splitter can be used as either a power combiner or a power divider, it is a reciprocal device. A coupler can be used to inject a second signal into a network, or as a means to sample a signal within a network (it is also reciprocal).

Couplers and splitters are usually three or four-port networks. N-way splitters are usually constructed as "corporate" splitters, where one two-way splitter feeds a pair of two-ways, which feed four two-ways, etc.

Coupler or splitter?

What's the difference between a splitter and a coupler? The way we define it, a coupler (usually) has four ports, uses no "internal" resistors and has one isolated port that is terminated. A splitter is (usually) a three-port, is non-directional, and requires internal resistors (like a Wilkinson) and has no isolated port. If you disagree or have anything to add to this distinction, tell us about it!

While we're on the subject of differences, let's answer this question for all time: what's the difference between a duck? A tree, because a motorcycle has no doors. Any other answer is incorrect.

Here is a clickable outline for studying power splitters and couplers:

Basic network theory

Properties of reciprocal and non-reciprocal networks

Properties of lossless networks

Properties of matched networks

Properties of three-port networks

Even and odd mode impedance

Gysel power splitters

Directional couplers

Hybrid (3-dB) couplers (90 degree and 180 degree)

Converting a branchline to a 180 degree hybrid

Quadrature couplers (90 degree hybrids)

Branchline couplers

Unequal-split branchline couplers

Coupled line couplers

Lange couplers

3 dB microstrip coupler

Short slot (Riblett) waveguide coupler

Overlay couplers

Saleh N-way power dividers

Traveling wave splitters (new for February 2010!)

180 degree hybrids

Rat-race couplers

Unequal-split rat-race couplers

Magic tees

Resistive power splitters

Resistive power tap

Adams splitter

Owen splitter

Wilkinson power splitters

Unequal-split Wilkinsons

Compact Wilkinsons

Lumped element Wilkinsons

Multi-stage Wilkinsons

Designing Wikinsons using Excel

N-way Wilkinsons

Lim-Eom three-way splitters