Enhancement of Antenna Array Bandwidth through Matching Impedance Modification Using Double Stub Matching on Feeding

Microstrip antennas are one of the most widely used types of antennas in various applications in communication systems. However, microstrip antenna experiences imbalance impedance, which in turn affects the performance of the antenna with narrow bandwidth as well as reducing the radiation emission of the radio wave. Therefore, in this paper increases bandwidth by changing the matching impedance using a double stub on the feeding antenna array. The double stub feeding is proposed for a dual-frequency band, in which at 2.4 and 5.8 GHz, respectively with identical dimension of antenna patch elements. This proposed structure is placed on the main supply of the microstrip antenna, specifically to match the antenna impedance with the transmission line impedance. From the simulation results, the appropriate impedance (Z) parameter values of 47 Ω at frequency of 2.4 GHz and 49 Ω at 5.8 GHz were correspondingly obtained. The return loss (RL) of -27 dB at 2.4 GHz and -36 dB at 5.8 GHz were also achieved. The voltage standing wave ratio (VSWR) has shown the best value of 1.09 and 1.03 respectively at 2.4 and 5.8 GHz. Improvements to the bandwidth extend beyond 3 times 2.4 GHz and 18 times at 5.8 GHz. Therefore, the proposed antenna can be used in Wireless Local-Area Network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX) frequency bands.