Terahertz (THz) links will play a major role in high data rate communication over a distance of few meters. In order to achieve this task, antenna designs with high gain and wideband characteristics will spearhead these links. In this contribution, we present different antenna designs that offer characteristics better suited to THz communication over short distances. Firstly, a single-element antenna having a dipole and reflector is designed to operate at 300 GHz, which is considered as a sub-terahertz band. That antenna achieves a wide impedance bandwidth of 38.6% from 294 GHz to 410 GHz with a gain of 5.14 dBi. Secondly, two designs based on the same dipole structure but with added directors are introduced to increase the gain while maintaining almost the same bandwidth. The gains achieved are 8.01 dBi and 9.6 dBi, respectively. Finally, an array of 1×4 elements is used to achieve the highest possible gain of 13.6 dBi with good efficiency about 89% and with limited director elements for a planar compact structure to state-of-the-art literature. All the results achieved make the proposed designs viable candidates for high-speed and short-distance wireless communication systems.

This paper presents a novel microstrip patch antenna design using slots and parasitic strips to operate at the n77 (3.3–4.2 GHz)/n78 (3.3–3.8 GHz) band of sub-6 GHz and n96 (5.9–7.1 GHz) band of sub-7 GHz under 5G New Radio. The proposed antenna is simulated and fabricated using an FR-4 substrate with a relative permittivity of 4.3 and copper of 0.035 mm thickness for the ground and radiating planes. A conventional patch antenna with a slot is also designed and fabricated for comparison. A comprehensive analysis of both designs is carried out to prove the superiority of the proposed antenna over conventional dual-band patch antennas. The proposed antenna achieves a wider bandwidth of 160 MHz at 3.45 GHz and 220 MHz at 5.9 GHz, with gains of 3.83 dBi and 0.576 dBi, respectively, compared to the conventional patch antenna with gains of 2.83 dBi and 0.1 dBi at the two frequencies. Parametric studies are conducted to investigate the effect of the parasitic strip’s width and length on antenna performance. The results of this study have significant implications for the deployment of high-gain compact patch antennas for sub-6 GHz and sub-7 GHz 5G wireless communications and demonstrate the potential of the proposed design to enhance performance and efficiency in these frequency bands.

Wireless communication technology integration is necessary for Internet of Things (IoT)-based applications to make their data easily accessible. This study proposes a new, portable L-shaped microstrip patch antenna with enhanced gain for IoT 2.4 GHz Industrial, Scientific, and Medical (ISM) applications. The overall dimensions of the antenna are 28 mm × 21 mm × 1.6 mm $(0.22{\lambda }_o$ × $0.17{\lambda }_o$ × $0.013{\lambda }_o$, with respect to the lowest frequency). The antenna design is simply comprised of an L-shape strip line, with a full ground applied in the back side and integrated with a tiny rectangular slot. According to investigations, the developed antenna is more efficient and has a greater gain than conventional antennas. The flexibility of the antenna’s matching impedance and performance are investigated through several parametric simulations. Results indicate that the gain and efficiency can be enhanced through modifying the rectangular back slot in conjunction with fine-tuning the front L-shaped patch. The finalized antenna operates at 2.4 GHz with a 98% radiation efficiency and peak gains of 2.09 dBi (measured) and 1.95 dBi (simulated). The performance of the simulation and measurement are found to be in good agreement. Based on the performance that was achieved, the developed L-shaped antenna can be used in a variety of 2.4 GHz ISM bands and IoT application environments, especially for indoor localization estimation scenarios, such as smart offices and houses, and fourth-generation (4G) wireless communications applications due to its small size and high fractional bandwidth.

This paper focuses on the 60 GHz band, which is known to be very attractive for enabling next-generation abundant multi-Gbps wireless connectivity in 5G communication. We propose a novel concept of a double-layer antenna, loosely inspired from standard log-periodic schemes but with an aperiodic geometry, reduced size, and a limited number of elements while achieving excellent performance over the entire 60 GHz band. To maximize the antenna’s efficiency, we have developed a design that differs from those traditionally used for millimeter-wave communication applications. We aim to simultaneously maximize the gain, efficiency, and bandwidth. The reflection coefficient of the proposed design achieves a bandwidth of 20.66% from 53.9 GHz up to 66.3 GHz, covering the entire frequency band of interest. In addition, this proposed structure achieves a maximum realized gain of 11.8 dBi with an estimated radiation efficiency of 91.2%. The proposed antenna is simulated, fabricated, and tested in an anechoic chamber environment. The measurement data show a reasonable agreement with the simulation results, with respect to the bandwidth, gain, and side-lobe level over the operational spectrum.

Wind power is a sustainable green energy source. Power forecasting via deep learning is essential due to diverse wind behavior and uncertainty in geological and climatic conditions. However, the volatile, nonlinear and intermittent behavior of wind makes it difficult to design reliable forecasting models. This paper introduces a new approach using variational auto-encoding and hybrid transfer learning to forecast wind power for large-scale regional windfarms. Transfer learning is applied to windfarm data collections to boost model training. However, multiregional windfarms consist of different wind and weather conditions, which makes it difficult to apply transfer learning. Therefore, we propose a hybrid transfer learning method consisting of two feature spaces; the first was obtained from an already trained model, while the second, small feature set was obtained from a current windfarm for retraining. Finally, the hybrid transferred neural networks were fine-tuned for different windfarms to achieve precise power forecasting. A comparison with other state-of-the-art approaches revealed that the proposed method outperforms previous techniques, achieving a lower mean absolute error (MAE), i.e., between 0.010 to 0.044, and a lowest root mean square error (RMSE), i.e., between 0.085 to 0.159. The normalized MAE and RMSE was 0.020, and the accuracy losses were less than 5%. The overall performance showed that the proposed hybrid model offers maximum wind power forecasting accuracy with minimal error.

The concept of substrate integrated waveguide (SIW) technology along with dielectric resonators (DR) is used to design antenna/array for 60 GHz communication systems. SIW is created in the substrate of RT/duroid 5880 having relative permittivityεr=2.23and loss tangenttan⁡δ=0.003. H-shaped longitudinal slot is engraved at the top metal layer of the substrate. Two pieces of the DR are placed on the slot without any air gap. The antenna structures are modeled using CST Microwave Studio and then the results are verified using another simulation software HFSS. Simulation results of the two designs are presented; first a single antenna element and then to enhance the gain of the system a broadside array of1×4is presented in the second design. For the single antenna element, the impedance bandwidth is 10.33% having a gain up to 5.5 dBi. Whereas in an array of1×4elements, the impedance bandwidth is found to be 10.70% with a gain up to 11.20 dBi. For the single antenna element and1×4antenna array, the simulated radiation efficiency is found to be 81% and 78%, respectively.