Designing and testing the quadrafilar helical antenna

Due to its approximately hemispherical radiation pattern, the quadrafilar helical antenna is commonly used in a wide variety of radio systems, especially in satellite communications. This paper is focused on appropriate design of this antenna in order to obtain the desired performance, like cardioid shaped radiation pattern and excellent circular polarization with a high axial ratio. Also, the antenna was examined numerically with 4NEC2 and tested in a radio laboratory.