Best Truncated Cone Ground Plane Reflector Dimensions for Helical Antenna?

Question

(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?

Thank you!

Answer 1

Interesting paper. As they say, at some point the cone becomes a horn antenna, then it's not really a helix any more. The elegance of the helix is its large gain, wide bandwidth and circular polarisation, from so little wire. Horn antennas are exactly the opposite.

The dimensions for the "optimal cone" are given on page 3 of the paper:

• Flat base diameter 0.75 λ
• Overall diameter 2.5 λ
• Height 0.75 λ

Where λ=176 mm, a design frequency of 1.7 GHz.