Directivity = Isolation (I) - Fwd Coupling (C) - Main Arm Loss (L)
{"Image DocumentName": "Directivity = Isolation (I) - Fwd Coupling (C) - Main Arm Loss (L)", "Image ImageDescription": "Directivity is a measure of how well a coupler can separate signals moving in opposite directions. (undesired leakage signal) (desired reflected signal) leakage. I. C. desired. result. Test port. L. Unfortunately, real signal-separation devices are never perfect. For example, let s take a closer look at the actual performance of a 3-port directional coupler. Ideally, a signal traveling in the coupler s reverse direction will not appear at all at the coupled port. In reality, however, some energy does leak through to the coupled arm, as a result of finite isolation. One of the most important parameter for couplers is their directivity. Directivity is a measure of a coupler s ability to separate signals flowing in opposite directions within the coupler. It can be thought of as the dynamic range available for reflection measurements. Directivity can be defined as: Directivity (dB) = Isolation (dB) - Forward Coupling Factor (dB) - Loss (through-arm) (dB) The appendix contains a slide showing how adding attenuation to the ports of a coupler can affect the effective directivity of a system (such as a network analyzer) that uses a directional coupler. As we will see in the next slide, finite directivity adds error to our measured results. Directional Coupler. Directivity = Isolation (I) - Fwd Coupling (C) - Main Arm Loss (L) \u00a9 Agilent Technologies, Inc", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}