Four-port Antenna Configuration in n78 5G Band for Energy Harvesting in Agricultural Sensors

In this paper, the authors have proposed a compact orthogonally arranged 4-port antenna configuration comprising series connected 3-element patch sub-array on each face having dimensions L1×W1 (19.4 mm×22.32 mm) for Element1 and Element3 and L1×W2 (19.4 mm×26.32 mm) for Element 2 designed on commercially available FR4 substrate (εr =4.3, tan δ =0.025). With respect to the center element (L1×W2), the sub array elements on its either side are equally and uniformly tapered so as to reduce the sidelobe level (SLL <-20dB) and the orthogonal arrangement of the 4-port configuration reduces mutual coupling (<-40 dB). The antenna system is suitable to work in the n78 (3.2-3.67 GHz) C band 5G having peak gain of around 6.55 dBi and radiation efficiency of about 35% having azimuthal angular width of 80° at the operating frequency 3.5 GHz. The configuration can thus be used to attain a precise 360° beam-steering aiding in energy harvesting for IoT based agricultural sensors.