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Special Issue on New Trends in Telecommunications Engineering  
**[PERSON] 1,2**(r)  
1R&D Department at Ignion, 08190 Barcelona, Spain; [EMAIL_ADDRESS]  
2 Smart Society Research Group, Universitat Ramon LLull, 08022 Barcelona, Spain  
This collection of research papers explores various aspects of antenna design and high-speed wireless communication, delving into the forefront of technology for modern telecommunications. Antennas are crucial components in wireless systems, enabling the transmission and reception of data. The papers in this collection investigate innovative antenna designs that cater to the growing demands of future-generation wireless applications, including 5G networks, Internet of Things (IoT) devices, and ultra-wideband (UWB) communication. These papers discuss antennas with characteristics such as super-wideband capabilities, dual-band operation, high gain, and multiple-input multiple-output (MIMO) configurations. Additionally, they explore novel techniques in order to minimize interference and optimize antenna layouts for improved performance. Furthermore, this collection delves into topics related to wireless communication efficiency, including error reduction methods and advanced optical nano-antenna designs for photonics applications. Overall, these papers represent the ongoing efforts to push the boundaries of antenna technology and enhance high-speed wireless communication systems for a connected and data-driven future. A brief summary of the papers can be found below. Ref. [1] paper proposes a high-dimension ratio, octagonal-shaped, super-wideband (SWB) monopole antenna. The antenna exhibits a frequency range of 3.71 to 337.88 GHz with good performance metrics such as \(|\)S11\(|\leq-\)10 dB, VSWR \(<\) 2, a bandwidth ratio (BR) of 91.07:1, and a very high bandwidth dimension ratio (BDR) of 6057.27. The antenna is designed on a Rogers 5880 dielectric substrate with compact dimensions of 14 \(\times\) 16 \(\times\) 0.787 mm\({}^{3}\). The simulated and measured results show good agreement, making the antenna suitable for future-generation mobile networks due to its strong radiation properties, compactness, and extremely wide bandwidth. Ref. [2] presents a design of an elliptical-shaped dual-band UWB notch antenna for wireless applications. The antenna incorporates corner cuts on a partial ground plane to achieve a UWB bandwidth and utilizes inverted-U-shaped and conductor-shaped resonators for dual-band notch characteristics. The proposed antenna has dimensions of 24 \(\times\) 32 mm\({}^{2}\) and offers a gain of 4.9 dB, a bandwidth of 2.5-11 GHz, and a stable radiation pattern. It rejects WLAN and ITU bands from 5.2 to 5.7 GHz and 7.2 to 8.5 GHz, respectively. The article discusses the evolution stages of the UWB antenna and the parametric analysis of the UWB notch antenna. Ref. [3] presents a compact antenna system with a multiple-input multiple-output (MIMO) configuration for mm-wave 5G-based Internet of Things (IoT) applications. The antenna elements are arranged to achieve significant field decorrelation and a dielectric layer is added to improve the radiation characteristics. The MIMO configuration has a size of 14 mm \(\times\) 20 mm and operates in the frequency range of 16.7 to 25.4 GHz. It achieves a peak gain of 8.47 dB, more than 80% total efficiency, and high isolation of over \(-\)30 dB. The design demonstrates wideband features, improved gain, and high isolation, making it suitable for mm-wave-based 5G applications. Ref. [4] explains a novel MIMO antenna system for ultra-wideband (UWB) applications is presented. The system consists of a 4 \(\times\) 4 array of antenna elements arranged in a plus-shaped configuration. The individual antenna element is a fractal circular ring structure with a modified partial ground plane. It operates in the frequency range of 2.67 GHz to 12 GHz, with a wide impedance bandwidth of 9.33 GHz. The system provides pattern and polarization diversity without the need for any isolation enhancement network.