Comparative study on stability of input impedance and total gain of Side Fed Bifilar Helix Antenna

Abstract

This paper presents the study of comparison of input impedance and total gain of Side Fed Bifilar Helix Antenna (SFBHA) with the height variation (in terms of wavelength) from Perfect Electric Conducting ground plane (PEC) which is fixed in size. The simulated results show that a 10λ×10λ size metallic ground plane has reasonable accuracy approximating the infinite PEC ground plane. The input impedance and Voltage Standing Wave Ratio (VSWR) variations are noticeable between the heights of 0.05λ to 0.35λ both in actual measurements and simulations. The observed variations above the height of 0.35λ are negligibly small. The simulated results of input impedance and VSWR are very similar to measured results. The simulated results and the measured results show the total gain pattern of SFBHA remains stable by varying the height of SFBHA above PEC. In this paper the performance comparison shows that electromagnetic performance of SFBHA till 0.35λ is better than Horizontal Dipole antenna (HD), Vertical rectangular Loop antenna (VL) and also another orientation of rectangular loop antenna that is Horizontal and Perpendicular Loop (H&PL).