Study of modified rectangular patch antenna for tuning resonant frequency in S-band

Tuning of resonant frequency of microstrip patch antenna is an important aspect for practical applications. A simple rectangular antenna was designed to resonate at 2.028GHz with a return loss (RL) value of -36.83dB. The antenna was designed using high frequency simulation software CST Microwave Studio. Modification of the antenna was carried out by introducing slit width of 1mm along one of the radiating edges which produces good matching with RL values above -53dB. Same slit with another orientation at an oblique angle to the feed point location results another frequency at the higher side of the resonant frequency, thus the antenna behaves as dual frequency antenna. Variations of the slit distance from feed point to radiating edges for different cases was studied and showed dual band characteristics with tuning of the resonant frequency within the same band (S-Band). The results indicated that RL values were not degraded, thus performance of the antenna was not disturbed with dual frequency behavior of the antenna with tuning of the frequency/frequencies.