Design of a compact antenna with stub using stepped impedance resonator

This research is mainly about modeling and measurement a compact antenna design with stub using stepped impedance via computer simulation technology (CST) simulation program. The dimension of microstrip antenna on FR4 material used in this research was 100 × 100 mm. In addition, the results include the comparison between the state of antenna before and after given the stub as well as before and after the length of the stub was changed. Then, do the variation changes the stub length and impedance step change in the vertical dimension (La), followed by step impedance variations horizontal width (Wt). The result shows that the design of the optimized stub affects the shift in the resonance frequency of the antenna. The resonance frequency of 2.4 GHz was shown when the stub length was 30 mm. In addition, by changing the width of the stepped impedance, we obtained new resonant frequency. From the simulation, four resonant frequencies that were shown include 0.7 GHz, 1.31 GHz, 2.4 GHz and 4.75 GHz. After the stub being added to the antenna, there was an increasing of TM₀₂ at the resonant frequency of 2.4GHz, and yet the resonance curve was still the same. TM₀₁ and TM₁₀ have indicated a better result when the antenna was located at the frequency of 800MHz and 1.3GHz. The proposed antenna has a gain 4.44dBi.