Bandwidth Enhancement of Microstrip Filtenna using Defected Ground Structure (DGS) for IoT Applications

A Defected Ground Structure (DGS) is employed to address the challenges of limited impedance bandwidth and increased subsystem complexity in IoT applications, which are common in traditional microstrip antennas. The proposed microstrip filtenna integrates a filter with a patch antenna using a 50 Ω quarter-wave microstrip line, built on an FR4 glass epoxy substrate. The design features a microstrip line feeding mechanism, a Stepped Impedance Resonator (SIR) filter, and a monopole radiating patch. Experimental results demonstrate significant bandwidth enhancement, with return losses of -22.0 dB at 5.5 GHz for the existing structure, and -13.58 dB at 6.5 GHz and -15.01 dB at 7.5 GHz for the proposed filtenna. The Voltage Standing Wave Ratio (VSWR) was also optimized to 1.15 at both 6.5 GHz and 7.5 GHz, indicating improved impedance matching. These advancements make the filtenna an ideal component for efficient and reliable IoT communication systems, enhancing its performance in high-frequency operations.