In the design of a log periodic one of the key steps is identifying the avarage characteristic impedance of a dipole. For a typical application see http://www.conformity.com/0005emc.html. The expression for this is given as 120*ln[(L/D) - 2.25)], where L is the length of the dipole and D the diameter. Does anyone know the origins of this expression, and how it was derived? The only time I have ever seen it is with reference to LPDA design.
Any help would be appreciated.
Red Flag Submitted
Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action.
Reply To This Thread
Posting in the Eng-Tips forums is a member-only feature.
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™s function at the center of their design considerations. Download Now
Metal 3D printing has rapidly emerged as a key technology in modern design and manufacturing, so itâ€™s critical educational institutions include it in their curricula to avoid leaving students at a disadvantage as they enter the workforce. Download Now
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now