Simulations and Measurements of a Prime Focus Dish With a Circular Septum Feed

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  • Author: Jeffrey Pawan and Rastislav Galuscak
This is the second article of two parts. This article concentrates on the impact of placing the previously simulated and measured feed [see July 2010 High Frequency Electronics] at the prime focus of a parabolic reflector. Since significant energy is reflected back into the feed, we wanted to determine how much effect this would have on the isolation between the two ports of the circularly-polarized feed. The simulation results and actual measurements were compared and found to correlate with very good accuracy. The match at each of the two ports is relatively unaffected at the design center frequency, whereas the port to port isolation is reduced by the reflections.