Design of 2.3/3.3/5.8 GHz antenna array for wireless communication in transportation systems

In this paper, an array of four element triangular-slot antenna with rectangular tuning stub for 2.3/3.3/5.8 GHz wireless communication is implemented on FR4 epoxy substrate. The triangular slot is fed by a 50 Ω probe that is placed in the center of the transmission line. From measurement based on VSWR = 2 or equal to the return loss of 9.53 dB, at the lower band of 2.3 GHz the resulting impedance bandwidth is 200 MHz (from 2.35 to 2.55 GHZ), at the middle band of 3.3 GHz is 490 MHz (from 3.76 to 4.25GHz), and at the upper band of 5.8 GHz is 280 MHz (from 5.57-5.85 GHz). The antenna gain measurement at 2.3 GHz frequency band is approximately 8 dB (simulation 9.2 dB), at 3.3 GHz is 7.5-8 dB (simulation 8-9 dB), and at 5.8 GHz is 7.8-8.5 dB (simulation is 8-9 dB). The antenna radiation pattern is shown to be bidirectional.