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Showing posts from May, 2020

Stacked Log-Periodic - 5GHz

While playing with my milling machine and little microwave PCB Yagi antennas, I wondered about increasing the bandwidth and still getting directional gain.  A Log-Periodic antenna looks almost exactly, but not quite unlike a Yagi... Practice is the best of all instructors -- Publius Syrus On a Log-Periodic, all the elements are driven, but each dipole is reversed by 180 degrees.  To make it on a single sided PCB, will require some links to wire up the dipoles.  I added a BNC connector and thin equilength coax to the feed points of the antennas. Stacked Log-Periodic 5GHz To reduce the amount of copper that needs to be milled out, I cut the board close to the radiators.  The bar at the back is for mounting and also serves as a reflective ground plane.  A log-periodic antenna is surprisingly compact and a little 5 dipole antenna will have a gain of about 3 dBi.   By carefully stacking two of them 0.75 Lambda1 centre to centre (54 mm), one should get another 2 to 3 dB of gain