Today, worldwide more than five billion of wireless devices are directly communicating for voice and data transmission. The amount of data utilization has increased remarkably and here comes 5G technology with more prominent features, offering high data rate, low latency rate, efficient EM spectrum utilization, an immense machine-2-machine communication, etc. The efficient implementation of 5G technologies requires efficient and compact antennas. This work presents a novel multiband rectangular dielectric resonator antenna for future 5G wireless communication system, having stacked radiator with semi-circular slots etched on the left and right sides of an upper radiator. Additionally, a semi-elliptical slots rectangular microstrip patch antenna of the same dimensions for the purpose of comparison is designed. 28 and 38 GHz, which are the proposed 5G bands by most researchers, are the core target of this work. Alumina with a high relative permittivity of 9.8 is used as a radiator in the design of DRA, while common in the design of both proposed antennas, Rogers RT/DUROID 5880 with a relative permittivity of 2.2 having standard thickness is used as substrate material. Both the proposed antennas have an overall same size of 13 × 11.25 mm 2. The proposed dielectric antenna resonates at 25.4, 34.6 and 38 GHz with 7.34, 4.04, and 3.30 GHz of wide impedance bandwidth covering the targeted 5G, 28, and 38 GHz bands, having a good return loss of-34.7,-31.8, and-33.5 dB, respectively. Further, the proposed dielectric antenna has a maximum radiation efficiency of 97.63%, with overall radiation efficiency greater than 90%, and maximum gain of 7.6 dBi is also noted. On the other hand, the proposed microstrip antenna resonates at 28 and 38 GHz with a 1.49 and 1.01 GHz of moderate impedance bandwidth, having-23.6 and-27.1 dB of satisfactory return loss. Further, the proposed patch antenna has a maximum radiation efficiency of 90.33% at 28 GHz, with overall radiation efficiency of greater than 84%, and moderate gain of 5.45 dBi is also noted. Both the proposed antennas have a nearly omnidirectional radiation pattern at resonance frequencies, with VSWR less than 2. Comparative study of the two proposed antennas regarding radiation efficiency, return loss, gain, data rate, and impedance bandwidth evidently shows that performance of DRA over MPA at millimeter wave is very good. The proposed antennas are simulated in CST Microwave studio v18.

In this paper, a coplanar waveguide-fed ultra-wideband-multiple-input and multiple-output (UWB-MIMO) antenna with a novel stub for isolation has been presented. The dimensions of the proposed antenna are 18 × 22 × 1.6 mm³. The proposed antenna is design on an FR4 substrate and simulated in CST studio. The |S₁₁| of the presented MIMO antenna is less than −10 dB between 2.8 and 13 GHz with an impedance bandwidth of 10.2 GHz. The envelope correlation coefficient (ECC) is less than 0.007 and diversity gain (DG) is greater than 9.97 dB. The proposed UWB-MIMO antenna is analyzed in terms of isolation, reflection coefficient, current distribution, ECC, DG, peak gain, multiplexing efficiency, and radiation pattern.

This work focuses on a compact circularly polarized wideband rectangular dielectric resonator antenna (RDRA) for X-band wireless applications. The wideband response of the RDRA is initially generated by a coaxial probe, a compact RDR, an air gap in the DR and a slot of rectangular shape in the ground. The circular polarization is achieved via incorporation of a unique feeding mechanism. The edge feeding of the RDRA with a coaxial probe generates the orthogonal modes in RDRA that make the design polarized circularly. The axial ratio performance is improved by adding a copper strip on the top of the DR. To validate the simulated results, the prototype design is fabricated and measured results are noted. For −10 dB reference value, the prototype has 59.74% impedance bandwidth (8.45–14.09 GHz). For 3 dB reference value of the axial ratio, the prototype has 9.24% Circular Polarization (CP) performance (10.084–11.084 GHz). The design has 6.5 dBic peak gain and 95.5% peak efficiency. Results show that simulated results are in close agreement with the measured results.

Beam steering antennas is essential part of various WCN (Wireless Communication Networks) such as radar and satellite communication. The increasing demand of high data rate, high SNR (Signal to Noise Ratio) and high gain, therefore pattern reconfigurable antennas are required to improve such properties. Beam steering is the technique of changing the main lobe direction of radiation. The constructive and distractive interference are used to steer the lobe in specific direction. Beam steering is necessary in various communications such as localization, satellite, tracking system and airborne application. Beam steering antenna decreases interference and power consumption and also increases directivity and gain. Beam steering antenna transmit and receive signals in specific direction. Beam steering antenna decreases interference and power consumption and also increases directivity and gain. The researchers are interested to find optimal beam steering solution for single and multi-point application. In past various techniques are used to achieve beam reconfigurable antennas. This paper presents, beam steering principle and their theory, beam steering techniques such as; Mechanical Steering, Beamforming, Switching Pin Diodes, Reflector and array antenna (Reflectarray), Parasitic Steering, Phase Shifters, Switched Beam Antennas, Metamaterial Antennas, Traveling Wave Antennas, Retro-directive Antennas, Integrated Lens Antennas (ILAS), merits and demerits and comparison among various techniques.