Loaded bifilar helical antenna with small radius and large pitch angle

A bifilar helical antenna (BHA) with a small radius (0.04 wavelengths) and large pitch angle (68 degrees ) is analysed using numerical techniques. To reduce the antenna length, the BHA is terminated with a resistive load. A six turn BHA with a resistive load of 400 Omega can generate a split beam of circular polarisation, whose direction moves to the horizontal plane (X-Y plane), as the frequency is increased. The frequency response for the gain shows that the BHA has a medium gain ranging from 7 to 10 dB.