Unequal Weighted Microstrip Array Antenna for Concrete Inspection Radar

Radar can be used for concrete inspection application to prevent structural failures. One of its components is the antenna. In this paper, a design of 1×4 microstrip array antenna integrated with unequal Wilkinson power divider using Dolph-Chebysev method on Epoxy FR-4 substrate with a dielectric constant of 4.3 was developed. Antenna is designed and simulated using CST software. The working frequency is in the ISM Band of 2.4–2.5 GHz with return loss −10 dB. The simulation results show that the array antenna operates at frequency 2.34–2.58 GHz or bandwidth of 243.6 MHz. In addition, the antenna has a gain of 4.39 dB, horizontal beamwidth of 27.8°, vertical beamwidth of 130.8°, front-to-back ratio of −21.87 dB, and sidelobe level of −13.2 dB. The measurement results show that the array antenna operates at frequency 2.35–2.59 GHz or bandwidth of 233 MHz. Moreover, the antenna has gain of 5.12 dB, horizontal beamwidth of 26°, vertical beamwidth 70°, front-to-back ratio of −20.22 dB, and sidelobe level of −17.45 dB.