Directional couplers are passive reciprocal networks. It is a four-port network where all four ports are ideally matched
and lossless. The wave incident in port 1 couples power into ports 2 and 3 but not into port 4. Nowadays, these components are
essential to all communication systems as they play an important role in the monitoring and measurement of signal samples
within an assigned operating frequency. In the first part of the project is to propose a broadside-coupled patch directional
coupler. The substrate used is RO4003C with the Ɛr = 3.38 and H = 0.8128 mm or 32 mil. A travelling-wave sectoral slot
resonator with three ports is presented in the second part. Computer Simulation Tool (CST) has been used to optimize the
magnitude of the directional coupler
