(Please excuse me if I'm bad at explaining I'm totally new to this topic)
For context, for this school project I'm doing, we have to design and build an antenna. I've made a helical antenna and its working alright so far, but I read online that a helical antennas gain improves depending on the type of its ground plane. (paper I'm referring to) From my understanding, a truncated cone works the best, but how are you meant to find the dimensions for building it? As in, how do you know how tall and wide it should be compared to the antenna itself?