## 3 Antennas with General Aspects Utilized for CubeSat
### Planar Phased Patch Antennas and Their Arrays
The design employs a microstrip patch configuration with materials like ITO (indium tin oxide) or AgHT (silver halide transparent) conductors, which allow for integration with solar panels, optimizing the utilization of space on CubeSats. The findings highlight an adequate GPS signal reception, compact size, and low-profile design, making it suitable for CubeSat deployment. However, challenges such as high resistive losses, reduced conductivity compared to traditional metals, and fabrication complexities impact the efficiency, gain, and durability in space conditions. Additionally,while the design supports GPS reception, it is not optimized for beam steering or dynamic beamforming, limiting its applicability for advanced CubeSat communication systems requiring directional adaptability and high-gain performance. A 1U CubeSat, which is a 100 mm cube, is built to support multiple functions. CubeSat satellites require antennas for TT&C, downlinking data, receiving signals, and facilitating intersatellite cross-links. The available area for antenna allocation in the minor CubeSat is 100 \(\times\) 100 mm\({}^{2}\), necessitating compact and lightweight antennas. CubeSat VHF-UHF antennas typically use deployable linear wire designs, mainly dipoles and their variations. Conversely, the machine-driven arrangement of these antennas introduces the danger of assignment collapse, as several small satellite missions have encountered issues due to these mechanical components. Many CubeSats operate within the VHF and UHF frequency bands [13]. Maintaining a communication link during the CubeSat maneuvers is crucial, and the challenge lies in achieving superior gain with compact patch antenna arrays fitted within the constrained space of the CubeSat. Reference [14] introduced a four-element antenna array for CubeSat cross-linking, with each element featuring two 14 \(\times\) 14 mm\({}^{2}\) transparent patch antennas mounted on a 1U CubeSat's sides. To ensure circular polarization, each patch is cropped. The authors simulated four arrays of patch antennas by applying a T-junction PD to feed them with sequential phase rotation. Every component has dimensions of 83 mm \(\times\) 69 mm \(\times\) 1 mm. A simulated S\({}_{11}\) of \(-\)17 dB (with solar cells) and a 10.20% bandwidth, ranging from 4.78 to 5.3 GHz, are achieved. In contrast, without solar cells, an S\({}_{11}\) of \(-\)21.5 dB at 5.1 GHz, with a bandwidth of 8.43%, was obtained [14]. In Ref. [15], a high-performance four-element patch antenna array tailored for a 3U CubeSat was suggested. This antenna is planned for attachment to one side (100 \(\times\) 100 mm\({}^{2}\)) of a 3U CubeSat, and it is specifically designed for Earth observation purposes. The primary goal is to enhance the gain of the antenna and attain circular polarization (CP) by positioning each adjacent pair of patches at a 90\({}^{\circ}\) angle and powering them through a Wilkinson power divider. This setup enhanced the signal strength and improved the isolation among ports, leading to optimal input impedance matching. It achieved a simulated gain, S\({}_{11}\), and BW of 8.22 dBi, \(-\)45 dB at 2.45 GHz, and 2.05 to 3.15 GHz, respectively. In Ref. [16], researchers developed an antenna for 3U CubeSat communication. The main design featured a transparent quartz substrate with square mesh lines arranged on a square ground plane. A significant challenge in this design was addressing the non-linear correlation between the copper meshed lines due to diminished radiation efficiency and gain. It achieved a transparency of 90%, a BW of 1.65%, an efficiency of 85.9%, an S\({}_{11}\) of \(-\)14.5 dB, and a total gain of 5.3 dBi at 2.43 GHz (28.44 \(\times\) 43.7 mm\({}^{2}\) dimensions). A notable benefit of this design is its high transparency, enabling it to be positioned over solar cells, allowing sunlight to pass through. This approach effectively halves the required area, since the antenna and solar panels occupy the same space.