Design of C-band Microstrip Antenna Using U-Slot and Defected Ground Structure

Abstract

Microstrip antennas are widely used in wireless communication systems because of their lightweight nature, compact size, and ease of fabrication. However, this type of antenna has inherent limitations, such as narrow bandwidth and low gain. To address these shortcomings, this study proposed a microstrip antenna operating in the C-band frequency range by applying a U-slot technique on the patch and a dumbbell-shaped DGS on the ground plane. The U-slot technique was used to enhance bandwidth, while the dumbbell-shaped defected ground structure (DGS) improved impedance matching and overall antenna characteristics without increasing antenna size. The antenna design process used analytical calculations for both the single-element and 1 × 4 array configurations, followed by three-dimensional full-wave electromagnetic simulations and fabrication on an FR-4 substrate. The antenna was measured using a vector network analyzer (VNA) to obtain the S-parameters. Simulation results showed that the 1× 4 array design achieved a return loss of -46.53 dB, a bandwidth of 376 MHz, a VSWR of 1.01, and a peak gain of 8.49 dBi. Measurement results indicated a return loss of -17.50 dB, a bandwidth of 480.81 MHz, and a VSWR of 1.31 at 5.4875 GHz. These results demonstrate that integrating the U-slot and dumbbell DGS effectively improves antenna performance. Overall, the proposed antenna meets the required specifications and shows potential for weather radar applications as a receiving antenna operating in the C-band front-end system.