## 1 Introduction
In [18], a low-profile wide beamwidth CP patch antenna on a suspended substrate is presented. A comprehensive review on UAV antennas operating at different bands with different specifications is given in [19; 20; 21]. In [22], a dual-band CP antenna for navigation systems is presented. Reference [23] presents a miniaturized square shaped CP antenna with gains of 5.14 dBi at 2.20 GHz and 4.5 dBi at 2.30 GHz. In [24], a dual-band and dual-port CP antenna for UAVs is given. In [25], a single-layer, dual-band, dual circularly polarized (CP) shared-aperture phased array antenna with wide beam scanning coverage is presented. In [26], a (CP) microstrip antenna with dual CP that is fed using a 3 dB 90\({}^{\circ}\) hybrid coupler to ensure dual-CP radiation is presented. A miniaturized CP antenna used in a wireless capsule endoscopy system at 2.45 GHz for industrial, scientific, and medical bands is proposed in [27]. Reference [28] presents a design to a CP antenna that can achieve broadband ARBW in the X-band. In [29], a patch array antenna with wideband circular polarization and a high gain is proposed by utilizing a hybrid meta surface (MS). The long-term average age of information (AoI)-minimal problem in an unmanned aerial vehicle (UAV)-assisted wireless-powered communication network (WPCN) is presented in [30]. This technique consists of a static hybrid access point (HAP), a mobile UAV, and many static sensor nodes (SNs) randomly distributed on multiple islands. In [31], a new design for the sum-channel radiating element with a circularly polarized patch monopole antenna monopulse feed design is introduced to operate at a center frequency of 2.21 GHz. This band can be used in the UAV applications. This paper introduces a novel miniaturized and compact microstrip patch antenna designed specifically for UAV applications, with dimensions of 40 \(\times\) 40 \(\times\) 1.6 mm\({}^{3}\), mounted on a low-cost FR-4 material as the dielectric substrate. The proposed antenna consists of a dual-sided geometry. The front side has a circular removed slot with several connected slots and two stubs at the corners, along with a feed line for signal input. The bottom side contains a partial ground plane with multiple slots of varying shapes, including vertical, horizontal, and square slots. These geometrical features are designed to enhance impedance matching and bandwidth, as well as to enable multi-band operation. The innovation of this work is highlighted by several key design features: the incorporation of truncated corners significantly enhances the CP characteristics, addressing challenges, such as polarization mismatch and multi-path distortion; the addition of two stubs positioned on opposite corners effectively achieves an axial ratio of less than 3 dB at the resonant frequencies of 2.4 GHz and 5 GHz, improving performance while maintaining a compact size; and the implementation of slots in the ground plane results in enhanced bandwidth and gain, making the antenna suitable for reliable wireless communication in UAV applications. Collectively, these innovative features promote the proposed antenna as a promising solution for WiFi communication in UAV applications. This paper is organized as follows: Section 2 details the proposed antenna design steps, performance characteristics, and parametric analysis of this antenna. Also, the circular polarization is discussed and the parameters that affect the CP and the return loss are introduced in this Section. Section 3 presents the antenna fabrication and the results and findings of this work. In Section 4, the experimental results are discussed and a comparison between the proposed antenna and several antennas presented in the literature is given. Finally, in Section 5, conclusion of this work is given.