**Abstract**

The objectives of this research include obtaining and verifying the impedance formula of the designed *bi-ellipse* microstrip antenna and correlating the results obtained through simulation and experimentation. The research also aims to obtain the structure and dimensions that provide optimal characteristics of the designed *bi-ellipse* microstrip antenna and produce a prototype at S, C and X-Band frequencies. This research produced the structure and dimensions of a *bi-ellipse* microstrip antenna that provide optimal characteristics of antenna. The characteristics results of the antenna parameters in this research include a 8x2 array, with a bandwidth value of around 100.0 MHz obtained at a working frequency of 7.09GHz (7.04 GHz - 7.14 GHz), with a reflection coefficient value of 0.02, Voltage Standing Wave Ratio (VSWR) of 1.06, return loss of 30.00 dB and a gain of 7.30 dB. For the 8x4 array, a bandwidth value of approximately 210.0 MHz is obtained at a working frequency range of 2.85GHz, which ranges from 2.74GHz - 2.95GHz, with a reflection coefficient value of 0.04, Voltage Standing Wave Ratio (VSWR) of 1.09, return loss of 27.06 dB and a gain of 8.19 dB. The results presented above fulfill the indicators of good antenna characteristics parameters applicable to radar communication systems.

**Keywords:** Microstrip Antenna, Array, *Bi-Ellipse*, Impedance Formula, Radar
