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This paper presents the design of a dual-band microstrip patch antenna for Wi-Fi that operates at 2.5 GHz and 5.8 GHz. The antenna contains a rectangular patch with two rectangular slots. The first slot is incorporated in the patch while the second slot is incorporated in the ground plane. The antenna is based on a microstrip fed rectangular patch printed on the FR-4 epoxy substrate with a dielectric constant of 4.4 and a thickness of 1.6 mm with patch size 24 mm × 21 mm. The simulated result shows that the realized antenna successfully works on dual-band and subsequently achieves a bandwidth of 100 MHz and 200 MHz as well as the return loss about -29.9 dB and -15.16 dB for 2.5 GHz and 5.8 GHz respectively. A stable omnidirectional radiation pattern is observed in the operating frequency bands. The antenna meets the required specifications for 802.11 WLAN standards.

An ultra wideband (UWB) radar cross-section (RCS) reduction metasurface has received attention in recent years. However, the majority of the research has concentrated on the physics and design of planar surfaces, which do not meet the standards of modern aerodynamics and aesthetics. In this paper, we offer a sophisticated strategy for designing a metasurface that can conform to the shape of any object, even those of moderate curvature, and can also achieve UWB RCS reduction by combining absorption, polarization conversion, and diffusion mechanisms. Firstly, an absorbing-polarization converter is designed, composed of a square patch with a truncated diagonal strip and ring. A thin Rogers RT/Duroid 5880 dielectric substrate layer is used in the structure, which is also appropriate for conformal conditions. The substrate layer and the ground plane are separated by an air gap to enhance the polarization conversion bandwidth (PCBW). For normal incident electromagnetic (EM) waves, the PCBW ranges from 10.8 to 31.3 GHz with polarization conversion ratio (PCR) values greater than 0.9 dB. Up to a 45∘ oblique incidence angle over the aforementioned band, the PCR efficiency is well maintained. Then, the optimized coding metasurface is formed by the Pancharatnam–Berry (PB) phase, consisting of meta-atoms “0” and “1” of the same size but different orientations, to realize the concept of cross-polarization diffusion. A theoretical investigation has been performed to analyze the RCS reduction performance of planar as well as conformal cylindrical surfaces. The results show that more than 10 dB of RCS reduction is experienced over UWB (10.8–31.3 GHz) for planar metasurfaces under linearly and circularly polarized incidence waves. Furthermore, the RCS reduction for cylindrical surfaces can be achieved in a similar frequency band above 10 dB up to an angle of 90∘. It can be deduced that our proposed flexible metasurface can be used as an absorber or a polarization converter and provide broadband RCS reduction, which is essential for multi-function and conformal stealth applications.

Background/Objectives: The major problems in WSN are the short-range of RF signals and the short life of batteries of each node. We develop a platform that uses the MAC protocols to avoid collisions between packets and decrease the data collection time. To overcome the energy challenges, the sleep modes, idle consumption, and others solutions provided to extend the node’s life period Methods/Statistical analysis: Based on the IoT applications, we configured different hardware (HW) to collect data from temperature,relative humidity (RH), and carbon dioxide (CO2), and access to this data, and these devices remotely through the internet. For this, the nodes, transceivers, batteries, and the gateway (GW) are analyzed. Additionally, it is configured with the frequency band or the radio frequency (RF) sensitivity to improve the performance of the system developed. Findings: Sensors, repeaters, and the GW were configured to work with each other and be accessed through the internet. The energy consumed on the experiment carried out has been reduced by more than 80% choosing LP modes and enable sleep algorithms over the Node’s OS where the time was also reduced around 80% in comparison with the available options. By set MQTT and SSH services, this application is scalable to be integrated with cloud services and be accessed by remote computers. Novelty/Applications: Finally, the lifelong period of nodes augmented drastically, more range between nodes is achieved and highly reliable data collected with low power consumption. Keywords: WSN; sensors; IoT; CO 2; temperature; relative humidity (RH)