Directional Couplers

Directional Couplers

Directional couplers are passive devices used in radio frequency (RF) and microwave systems to split or combine electromagnetic signals. They are designed to transfer power from one transmission line to another, while allowing the signal to flow in only one direction. Directional couplers are commonly used in communication systems, radar systems, and test and measurement equipment. Directional couplers consist of two or more coupled transmission lines, usually in a symmetrical arrangement. The main transmission line, also known as the through-line, carries the input signal, while the coupled line, also known as the coupled port, carries a portion of the signal to the output port. The amount of power transferred to the output port depends on the coupling factor, which is determined by the physical characteristics of the coupler. Directional couplers are classified based on their coupling factor, which can range from a few percent to over 50%. The most common types of directional couplers include the single-section coupler, the multi-section coupler, the branch-line coupler, and the hybrid coupler. Each type has its own advantages and disadvantages, and is chosen based on the specific application requirements. Directional couplers are used in a variety of applications, including power monitoring, signal sampling, and impedance matching. They are also used in antenna systems to split the signal between multiple antennas, or to combine the signals from multiple antennas. In addition, directional couplers are used in test and measurement equipment to measure the power and frequency response of RF and microwave devices.

RF, microwave, transmission lines, coupling factor, power monitoring

— Jason Smith

CITATION : "Jason Smith. 'Directional Couplers.' Design+Encyclopedia. https://design-encyclopedia.com/define/directional-couplers?E=318578 (Accessed on October 14, 2026)"