Design, Simulation and Performance Analysis of Yagi Antenna Array For VHF Radar

Abstract

This paper introduce a design and simulation of VHF yagi-uda antenna array to be used in radar application. A single folded dipole yagi-uda antenna is simulated and optimized at 165MHz then a yagi uda antenna array with two rows, each row has 6 elements is designed and simulated. The same array is analyzed by introducing a phase shift between the two rows and with using two different elements spacing, $0.5 \lambda$ and $0.7 \lambda$. Simulation is done using matlab, and parameters of directivity and side lobe levels are investigated for each array. From simulation results, as the distance between antenna elements is increased from $0.5 \lambda$ to $0.7 \lambda$, the directivity is increased, side lobe level in azimuth is increased and side lobe level in elevation is the same. Also, rotating the beam of the array through a phase shift of 65 degree will not affect azimuth side lobe level but in contrast, elevation side lobe level will increase and the directivity is reduced by a small amount. Also in this paper, blake chart is drawn for the proposed VHF yagi-uda antenna array. The maximum free space range have been taken to be 300 km, 0 degree tilt angle and for the antenna height, two heights have been used 2.7 meters and 4.7 meters, the chart have been investigated for each antenna height and for both element spacing, $0.5 \lambda$ and $0.7 \lambda$, with and without a phase shift between the rows of the array.