A Compact 2 by 2 Printed Yagi-Uda Antenna Array with Enhanced Isolation and Gain

This paper presents the design and experimental evaluation of a compact 2 by 2 printed Yagi antenna array at 5.8 GHz. The planar array has a rectangular grid with d
_x
=0.5λ and d
_y
=0.2λ. To alleviate performance degradation due to the reduced element spacing of 0.2λ, parasitic dipoles are placed in the closely- spaced stacked Yagi array. The designed parasitic elements improve the isolation between the stacked Yagis by over 15 dB and increase the gain of 2×2 array from 7.76 dB to 9.343 dB. Measurements of the fabricated prototype confirm the simulated predictions. The proposed technique is a low-cost solution for improving the achievable gain of a planar printed Yagi array in constrained form factor designs.