This paper presented the design and simulation of 24 GHz microstrip patch antennas for use in FMCW (frequency-modulated continuous waves) radar systems, which have a high resolution and accuracy that make them a preferred technique for detecting small targets like drones. The antenna’s design has a major impact on the radar system’s performance. In this work, we combined the characteristics of a patch array antenna, such as its small size and ability to integrate with other devices, with a parabolic reflector, which has a high directivity. Electromagnetic simulation was conducted using CST Microwave Studio. The results show that the reflector shape and number of antennas significantly influence the antenna characteristics. The 8 rectangular microstrip antennas on the reflector shape provided the highest gain of over 24 dBi in comparison with the earlier works, the highest radiation efficiency of about 99%, the direction of the main lobe of 49 degrees is relatively high, and the side lobe level of −3.3 dB is relatively low while maintaining a narrow beamwidth suitable for long-range drone detection and a great power of 60.6 dB. The results of this work can help create an effective 24 GHz antenna for FMCW radar systems that will reliably identify drones, a crucial capability for public safety and airspace security.