Design and analysis of a dual-band polarization converting metasurface is presented in this paper. The proposed converter, which consists of two square split ring resonators (SRRs), exhibits peak resonances at frequencies of 5.6, 7.3, 8.8, 15.1, 15.9 GHz. The surface behaves as a polarization converter for linearly polarized incident waves in two frequency ranges, i.e., 5.49.0 GHz with a polarization conversion ratio (PCR) 93%, and 14.616.1 GHz with a PCR 99%). The size and thickness of the unit cell are, respectively, 0.126o and 0.057o, where o is the largest wavelength (corresponding to the lower frequency). The mechanism of polarization conversion is studied by examining the surface currents for all the resonance frequencies. Both simulated and experimental results reveals that the polarization converter can be utilized in C-, X- and Ku-band applications.

This study designed and analyzed an artificial magnetic conductor (AMC)-based fabric antenna for body-centric communication. The antenna was made of felt and had a loss tangent of 0.044 and relative permittivity of 1.3. The proposed antenna was built to function in the frequency band centered at 2.45 GHz, widely used in wireless communication devices. The antenna’s performance was evaluated using the electromagnetic simulation software CST MWS. A 50 Ω SubMiniature version connector was used to excite the proposed antenna. A 2 × 2 AMC array was integrated into the antenna below it to improve its performance in terms of radiation efficiency, gain, and backward radiation reduction. The antenna and AMC array were fabricated on flexible fabric substrates. The total volume of the AMC-integrated antenna is 0.55λ ₀ × 0.55λ ₀ × 0.016λ ₀ . It was demonstrated that adding an AMC array enhanced the radiation properties of the antenna and significantly decreased its back lobes. The on- and off-body maximum gains of the AMC-integrated antenna are (≥ 4.11 dBi) and 5.23 dBi, respectively. Furthermore, employing the AMC array, a significant reduction in the specific absorption rate value, which is (≤ 0.43 W/kg) for human body tissue chest/back and (≤ 0.75 W/kg) for human body tissue arm, was obtained, ensuring safety for human use. The simulated and measured results were in agreement. The tested on- and off-body radiation efficiencies in the frequency band centered at 2.45 GHz is (>67%) and (>83%), respectively. The proposed antenna can potentially be used in various applications such as healthcare monitoring, wearable electronics, and Internet of Things (IoT) systems, where reliable and efficient communication is required in a body-centric environment.

The increasing demand for wireless communication in wearable devices has led to the need for wearable antennas with a low profile, flexibility, robustness, low SAR, and acceptable on-body performance for WBAN applications. This study presents a low-profile dual-band wearable antenna for WBAN applications operating at 2.45 and 5.8 GHz. The antenna is integrated with a 3 × 3 artificial magnetic conductor array to reduce backward radiation and improve performance when worn on the human body. It is designed and fabricated on a 2 mm-thick flexible felt substrate with a relative permittivity of 1.3 and loss tangent of 0.044. A 0.17 mm-thick superconductive shielded material is used as conductive material for the antenna and AMC array. The proposed antenna and AMC array have overall volumes of 0.41λ ₀ × 0.45λ ₀ × 0.016λ ₀ and 0.83λ ₀ × 0.83λ ₀ × 0.016λ ₀ , respectively. Results indicate that the AMC structure enhances the antenna’s gain, radiation efficiency, and bandwidth. The use of AMC reduced the SAR by greater than 98% for 1 and 10 g of human tissue at 2.45 and 5.8 GHz. The proposed design is suitable for WBAN applications due to its low profile, flexibility, robustness, low SAR, and acceptable on-body antenna gain and bandwidth.

In this paper, antipodal Vivaldi antenna is designed for 5th generation (5G) mobile communication and Ku-band applications. The proposed designed has three layers. The upper layer consists of eight-element array of split-shaped leaf structures, which is fed by a 1-to-8 power divider network. Middle layer is a substrate made of Rogers 5880. The bottom layer consists of truncated ground and shorter mirror-image split leaf structures. The overall size of the designed antenna is confined significantly to 33.31 × 54.96 × 0.787 (volume in mm${}^3$), which is equivalent to 2$\lambda$${}_o$× 3.3$\lambda$${}_o$× 0.05$\lambda$${}_o$ ($\lambda$${}_o$ is free-space wavelength at 18 GHz). Proposed eight elements antenna is multi-band in nature covering Ku-bands (14.44–20.98 GHz), two millimeter wave (mmW) bands i.e., 24.34–29 GHz and 33–40 GHz, which are candidate frequency bands for 5G communications. The Ku-Band is suitable for radar applications. Proposed eight elements antenna is very efficient and has stable gain for 5G mobile communication and Ku-band applications. The simulation results are experimentally validated by testing the fabricated prototypes of the proposed design.