## 1 Introduction  
Unmanned aerial vehicles (UAVs) are aerial platforms without a human pilot on board [1]. They are useful for operations in dangerous environments, that present high risk for human intervention. UAVs are used in various sectors, such as science, civilian operations, and the military, for the purpose of covering an expanded geographic region with high-speed data collection for remote sensing applications. This includes geographical data observation, soil monitoring, and precision agriculture [1]. They also play a significant role in disaster management systems. Providing on-demand communication is necessary in the event of a disaster because there may be no communication network infrastructure [1]. Currently, one of the most common research areas in wireless communication technology is microstrip patch antenna design [2]. Antennas have gained significant popularity in the field of UAVs due to their compact size and lightweight design. Antennas for UAVsare used to establish wireless communication links [2]. These antennas are designed to operate within specific frequency bands, such as WiFi bands, which are commonly used for UAV communication and control [3]. By operating within these bands, the antenna ensures compatibility with standard WiFi protocols, facilitating seamless connectivity with ground stations and other WiFi devices [3]. Antennas in UAV applications require optimization of the antenna's impedance matching, radiation pattern, gain, efficiency, bandwidth, and environmental ruggedness [4]. By carefully adjusting the dimensions of the patch, substrate properties, feeding mechanism, and ground plane configuration, the desired performance parameters can be achieved while adhering to the size, weight, and environmental constraints of UAVs [5]. In recent years, the utilization of circular polarization (CP) antennas has become increasingly prevalent [5]. This is primarily due to their ability to address challenges, such as multi-path distortion and polarization mismatch, more effectively than linear polarization [5]. Circular polarization eliminates the need for precise alignment between transmitting and receiving antennas [6]. Moreover, CP antennas offer advantages, such as affordability, compactness, and ease of integration, which have contributed to their widespread adoption in satellite and mobile communication systems over time [7]. With the rapid development of the modern wireless communications system, antenna design has turned to focus on circular polarization and small simple structures that can be easily fabricated. In the literature, various CP antennas operating at different bands are presented that meet the requirements of current wireless communications. In [8], a comprehensive investigation of signal propagation and performance under multiple frequencies is conducted, from mid-band to mmWaves range (3.5, 6, 28, and 60 GHz). In [9], a low-profile CP antenna is presented with a wide 3 dB ARBW. In [10], a dual frequency CP truncated square aperture patch antenna is proposed with a slant strip line and an L-shaped slot for wireless local area network (WLAN) applications with lower band gains of 2.51 dBi and 2.98 dBi, and upper band gains of 3.51 dBi and 3.49 dBi. In [11], a dual-band CP planar monopole antenna is presented, and [12] proposes a dual-band microstrip patch antenna design based on a two-layer stacked patch for GPS and WiFi purposes. In [13], a low-profile dual-band directional antenna operating at both 2.4 and 5 GHz for WLANs is used for UAV applications with gains of 5.2 and 7.0 dBi, in the 2.4 and 5.8 GHz bands, respectively. In [14], a crescent-shaped slot antenna is presented with the loading of a circular patch that greatly enhances the 3 dB ARBW. In [15], a quad-band CP antenna, for applications of a global navigation satellite system (GNSS), 5G, and WIFI-6E, is designed. In [16], a low-profile, four-port dual-band monopole multiple-input-multiple-output (MIMO) antenna array is presented. In [17], a miniaturized high-gain flexible UAV antenna is presented.