Communication technology is increasingly pervading everyday life. The rapid progress in wireless communication besides the increasing interest in wearable antennas and electronics in civil, medical, sport wear and military domains promises to replace wiredcommunication networks in the near future in which antennas are in more important role. Recently, there has been growing interest in the antenna community to merge between wearable systems technology, Ultra-Wideband (UWB) technology and textile technology. All these together have resulted in demand for flexible fabric antennas, which can be easily attached to a piece of clothing. In this paper, three different structures of UWB antennas using clothing materials and suitable for wearable application were fabricated and presented. The substrate of the designed antennas was made from jeans textile material, while radiating element and ground plane are made out of copper tape. The operating frequency of all three designs is between 3 GHz and 12 GHz. Measured results are compared with simulations and good agreement was observed.

The incoming 5G technology requires antennas with a greater capacity, wider wireless spectrum utilisation, high gain, and steer-ability. This is due to the cramped spectrum utilisation in the previous generation. As a matter of fact, conventional antennas are unable to serve the new frequency due to the limitations in fabrication and installation mainly for smaller sizes. The use of graphene material promises antennas with smaller sizes and thinner dimensions, yet capable of emitting higher frequencies. Hence, graphene antennas were studied at a frequency of 15 GHz in both single and array elements. The high-frequency antenna contributed to a large bandwidth and was excited by coplanar waveguide for easy fabrication on one surface via screen printing. The defected ground structure was applied in an array element to improve the radiation and increase the gain. The results showed that the printed, single element graphene antenna produced an impedance bandwidth, gain, and efficiency of 48.64%, 2.87 dBi, and 67.44%, respectively. Meanwhile, the array element produced slightly better efficiency (72.98%), approximately the same impedance bandwidth as the single element (48.98%), but higher gain (8.41 dBi). Moreover, it provided a beam width of 21.2° with scanning beam capability from 0° up to 39.05°. Thus, it was proved that graphene materials can be applied in 5G.

In the 5G mobile system, new features such as millimetre wave operation, small cell size and multi beam are requested at base stations. At millimetre wave, the base station antennas become very small in size, which is about 30 cm; thus, dielectric lens antennas that have excellent multi beam radiation pattern performance are suitable candidates. For base station application, the lens antennas with small thickness and small curvature are requested for light weight and ease of installation. In this paper, a new lens shaping method for thin and small lens curvature is proposed. In order to develop the thin lens antenna, comparisons of antenna structures with conventional aperture distribution lens and Abbe’s sine lens are made. Moreover, multi beam radiation pattern of three types of lenses are compared. As a result, the thin and small curvature of the proposed lens and an excellent multi beam radiation pattern are ensured.

Recently, helical antennas had been used as a very small implantable antenna in a capsule endoscopy system. For a helical antenna, a normal-mode helical antenna (NMHA) is promising because of its small size and the completeness of an antenna design method, which has already been established. However, in the human body, the effects of human tissues on the electrical characteristics of an NMHA were not clarified. The most important aspect is to determine the self-resonant structures. In this letter, a deterministic equation is derived for the self-resonant structures of an NMHA in the human body. By utilizing simulation results of an electromagnetic simulator, a capacitive reactance equation is deduced based on the electric field distributions around an antenna. An inductive reactance equation is obtained by modifying the equation of free space to the condition of inside a dielectric material. Finally, by equating the capacitive and inductive reactance equations, the self-resonant equation is determined. The accuracy of the equation is ensured through the agreements of the antenna structures given by equations and electromagnetic simulations. Moreover, by fabricating an NMHA and a human body phantom, the measured results are obtained. The self-resonant structure is ensured through the measured results.