In this article, a novel uniplanar ultra‐wideband (UWB) stop frequency selective surface (FSS) was miniaturized to maximize the gain of a compact UWB monopole antenna for microwave imaging applications. The single‐plane FSS unit cell size was only 0.095λ × 0.095λ for a lower‐operating frequency had been introduced, which was miniaturized by combining a square‐loop with a cross‐dipole on FR4 substrate. The proposed hexagonal antenna was printed on FR4 substrate with coplanar waveguide feed, which was further backed at 21.6 mm by 3 × 3 FSS array. The unit cell was modeled with an equivalent circuit, while the measured characteristics of fabricated FSS array and the antenna prototypes were validated with the simulation outcomes. The FSS displayed transmission magnitude below −10 dB and linear reflection phase over the bandwidth of 2.6 to 11.1 GHz. The proposed antenna prototype achieved excellent gain improvement about 3.5 dBi, unidirectional radiation, and bandwidth of 3.8 to 10.6 GHz. Exceptional agreements were observed between the simulation and the measured outcomes. Hence, a new UWB baggage scanner system was developed to assess the short distance imaging of simulated small metallic objects in handbag model. The system based on the proposed antenna displayed a higher resolution image than the antenna without FSS.

Despite the fact that OFDM has numerous features, the high peak-to-average power ratio (PAPR) deems one of the challenging disadvantages face by the system in the real applications. The high PAPR limits the OFDM signal efficiency on the transmitter side. Thus many PAPR alleviation approaches have been suggested in the past. Partial transmit sequences (PTS) has been accounted as one of the successful procedures for decreasing the high PAPR; with the consideration that the computational complexity of the PTS method regarded high relatively. Moreover, improving the PAPR mitigation performance of the PTS algorithm relies upon the number of the partitioned subblocks, the number of the phase rotation vectors, and the kind of the segmentation scheme utilized. This article presents new segmentation schemes to enhance the PAPR mitigation execution without further intricacy on the system. Adjacent shifting segmentation scheme (Ad-Sh-PTS) and rows exchange of interleaving segmentation schemes (IL-Ex-PTS) are proposed depending on the two well-known segmentation schemes of adjacent partition PTS (Ad-PTS) and interleaving partition PTS (IL-PTS). The simulation demonstrates that the suggested algorithms can accomplish mitigation in PAPR preferable compared to the traditional schemes, Ad-PTS and IL-PTS schemes.

The optimal generation scheduling (OGS) of hydropower units holds an important position in electric power systems, which is significantly investigated as a research issue. Hydropower has a slight social and ecological effect when compared with other types of sustainable power source. The target of long-, mid-, and short-term hydro scheduling (LMSTHS) problems is to optimize the power generation schedule of the accessible hydropower units, which generate maximum energy by utilizing the available potential during a specific period. Numerous traditional optimization procedures are first presented for making a solution to the LMSTHS problem. Lately, various optimization approaches, which have been assigned as a procedure based on experiences, have been executed to get the optimal solution of the generation scheduling of hydro systems. This article offers a complete survey of the implementation of various methods to get the OGS of hydro systems by examining the executed methods from various perspectives. Optimal solutions obtained by a collection of meta-heuristic optimization methods for various experience cases are established, and the presented methods are compared according to the case study, limitation of parameters, optimization techniques, and consideration of the main goal. Previous studies are mostly focused on hydro scheduling that is based on a reservoir of hydropower plants. Future study aspects are also considered, which are presented as the key issue surrounding the LMSTHS problem.

Abstract-A quad band-notched compact ultra-wideband (UWB) patch antenna to operate on the industry, scientific, and medical (ISM) bands are presented in this study. A modified hexagonal patch vertex-fed with a coplanar waveguide (CPW) is fabricated on an FR-4 substrate with size of 43 × 28 × 1.6 mm 3 and fractional bandwidth of 133%. The compact antenna operates at a frequency of 2.45 GHz, which is often required for the efficient performance of ISM utilisation. The existing bands share the same bandwidth as that of UWB systems. Therefore, a notched band at 3 GHz for worldwide interoperability for microwave access (WiMAX), and a further resonance band at 2.45 GHz for ISM are generated by implementing a meander-line strip on the antenna. Furthermore, the design demonstrates a couple of F-shaped slots and an inverted diamond-shaped slot on the patch. Moreover, a pair of Jshaped slots is loaded on the ground plane. The downlink C-band, wireless local area network (WLAN), and downlink X-band are rejected by the proposed slots, respectively. The current distribution, gain, radiation efficiency, and quad notched parameters of the proposed antenna are studied by using CST software. The demonstrated prototype covers an ISM band at (2.2 GHz-2.6 GHz) with a return loss of −23.45 dB and omnidirectional radiation patterns. A good agreement is observed between measured and the simulated results. This paper has presented a solution for both interference and miniaturised issues.