A Compact Super Wideband Planar Monopole Antenna for Microwave Imaging Applications

In this work, a small planar super wideband monopole antenna of dimension 35 mm × 30 mm × 0.8 mm is designed to offer the 37.2 GHz bandwidth in the 2.8–40 GHz (14.28:1) frequency range. An extensive relative bandwidth that is greater than 173%, bandwidth to dimension ratio of 1904, highest gain of 6.1dBi and radiation efficiency almost equal to 80% are realized from this antenna. Several contemporary and futuristic wireless technologies such as commercial ultra-wideband (3.1–10.6 GHz), ISM bands (5.725–5.875 GHz, 24–24.25 GHz), WiMAX (3.3–3.8 GHz, 5.25–5.825 GHz), WLAN (5.15–5.35 GHz, 5.725–5.825 GHz), S(2–4 GHz)-C(4–8 GHz)-X(8–12 GHz)-Ku(12–18 GHz)-Ka(27–40 GHz) bands, and 5G NR bands (n77, n78, n79, n102, n104, n257, n258, n260, n261) are within the antenna’s spectrum range (2.8–40 GHz). The applicability of this bulb-alike antenna for microwave imaging is tested experimentally by studying the antenna’s impedance band, transfer function and group delay responses in vicinity of soil and wood exteriors of varying thicknesses. Moreover, C-scan result is incorporated for justifying the antenna’s applicability in microwave imaging application.