# Antenna Designs for 5G/IoT and Space Applications
## 2 Short Presentation of the Papers  
[PERSON] et al. [1] presented a comprehensive survey of antennas used for 120 CubeSat missions from the period from 2003 to 2022, as well as their techniques and approaches. The aim of this paper is to provide an introductory guide on CubeSats antennas for CubeSat enthusiasts and a state of the art for CubeSat designers in this ever-growing field. Itpresents a background on CubeSats and their subsystems to provide newcomers with the fundamental knowledge on CubeSat technologies. In addition, the authors investigated different designs for CubeSats, including single-element antennas and antenna arrays, as well as the aim of capturing the current and future CubeSat trends from an antenna point of view. They also proposed a pictorial representation of how to select an antenna for different types of CubeSat missions. [PERSON] et al. [2] surveyed the recent base station antenna (BSA) designs for 5G Sub-6 GHz and their challenges. The authors provided a comprehensive summary of BSAs with particular interest placed on lower microwave bands in sub-6 GHz range. They also provided a brief discussion on the development of the BSA technologies through mobile generations, as well as a detailed discussion on the challenges associated with the BSAs. These challenges include the achieving wide impedance bandwidth while meeting the port-to-port isolation requirements, making the radiating elements of one band transparent to another band and vice versa without causing scattering and undesirable effects on the radiation pattern and meeting the size constrains. The authors have also provided a cohesive list of design techniques adopted to overcome the aforementioned challenges. [PERSON] et al. [3] proposed a graphene plasmonic two port MIMO antenna for 6G/IoT applications. The proposed antenna operates in Terahertz frequency band (e.g., 3.2-3.8 THz) and provides good radiation performance. A technique that the authors used to reduce the mutual coupling between radiating elements is the etching of the dumbbell-structure metamaterial (MTM) unit cell in the ground plane. They reported a high isolation of \(-55\) dB between radiating elements, simulated gain of 7.23 dB and low channel capacity loss of 0.006. [PERSON] et al. [4] presented an ultra-wideband pentagonal fractal antenna for new-field microwave imaging applications. The proposed compact antenna has a size of 24 mm \(\times\) 30 mm \(\times\) 0.787 mm and used the Rogers RT/Duroid 5880 dielectric substrate. The authors used the co-planar waveguide (CPW) feed technique and trapezoidal ground plane to achieve low losses and to enhance the impedance matching, respectively. The proposed antenna provides a fractional bandwidth of 123.56%, and a measured \(-10\) dBi impedance bandwidth of 9.7 GHz (3-12.7 GHz) and a total gain of 3.6 dBi at 8.5 GHz. [PERSON] et al. [5] designed and proposed a compact single-input single-output antenna with a slotted decahedral patch for 5G applications. The main idea is the use of dechedral patch with the eight-pointed star-shaped slot geometry and two rectangular grooves to enhance the antenna's performance and to achieve the stability of the radiation pattern across the wide \(-10\) dB impedance bandwidth (e.g., 23-29.9 GHz). The proposed antenna has a total size of 13 mm \(\times\) 13 mm \(\times\) 0.787 mm and achieves a wide \(-10\) dB impedance matching of 6.84 GHz (23.1-29.9 GHz), 89.4% radiation efficiency, a gain of 6.56 dBi and reflection coefficient of \(-21.5\) dB at 29 GHz. [PERSON] et al. [6] presented a multi-circular loop planar antenna array for next generation mm-wave communication system. The proposed antenna consists of multi circular loop rings, uses Rogers 5880 substrate and has a small size of 18.5 mm \(\times\) 12.5 mm \(\times\) 0.254 mm. To enhance the performance (e.g., \(-10\) dB bandwidth, gain and reflection coefficient) of the proposed antenna, the authors used a partial ground plane with a square slot, and four elements.