Printed concave‐like slot for bandwidth enhancement of inset‐fed patch antenna on metallic surfaces

s A rectangular patch antenna design with fundamental TM100 mode for on‐metal applications is presented. The patch is excited by an inset‐fed microstrip feedline and optimized for better performance by varying the inset‐fed parameters. The patch is then loaded with a circular slot of radius Ry at its center to create additional resonance at TM11 mode. The radius Ry is varied to elongate the circular slot into biconcave shape, to increase its electrical length. Thus, manipulating TM11 mode with respect to TM100 mode to achieve wideband by combining the two resonances using overlap technique. Equations of the resonance of the circular slot is stated and so is the surface area of the biconcave. The resulting antenna is etched on a 130 μm‐thick RO3003 microwave laminate and stamped on a metallic pipe cladding using the pipe as the metallic ground. The realized bandwidth is enhanced by 13% with reasonable achieved directivity. The simulated and measured results agreed reasonably with marginal discrepancy.