This paper presents a novel low-cost integrated multiband antenna design customized for smartwatch applications and wearable devices. The design consists in using a broadband planar patch antenna with circular microstrip lines and a miniaturized feeding-point with a structure of 30×30×1.6mm³, and it is easy to deploy inside the smartwatch and cost-effective for the wearable device industry. The parametric study and final dimensions of the design and the measured results of the reflection and radiation pattern are discussed. The antenna with maximum gain up to 6.6dBi and S₁₁ up to 22dB exhibits excellent performance for all the frequencies required in wearable systems such as 1.9GHz, 2.3GHz, 2.4GHz, 2.6GHz, 5.2 GHz, and 5.8GHz. We drew a comparison between similar research and this work in terms of antenna performance. Furthermore, we investigate the specific absorption rate (SAR) performance of the antenna for the smartwatch application, using both human hand wrist multilayer and SAM head mouth models. The SAR results in different positions for all the frequencies are compared to the Federal Communication Commission (FCC) standards.

The objective of the present study is to evaluate the Specific Absorption Rate (SAR) within the human head model exposed to the radiation of planar monopole antenna with T-shaped coupling feed and an inductive shorting strip. The presented design has a compact structure, a planar configuration and occupying a small size of 36×20mm2. Two wide bands can be generated by the proposed antenna 546 MHz (734-1280 MHz) and 1066 MHz (1934-3000 MHz) for the LTE/WWAN/WLAN internal mobile phone. The antenna performance parameters comprising return loss, radiation patterns, and gain are discussed. In this research work four different human head models have been implemented: homogenous spherical head, spherical seven layer model, Specific Anthropomorphic Mannequin (SAM) phantom and HUGO human head model. On the other hand the effects of operating frequency and gap distance between the mobile phone antenna and the human head model on distributions of the SAR inside the human head are investigated. All the simulations are done for three different distances between the antenna and the head model (5 mm, 10 mm and 20 mm). Moreover, the SAR levels for the head tissues are calculated in accordance to the two currently accepted standards: Federal Communications Commission (FCC) and International Commission on Non-Ionizing Radiation Protection (ICNIRP).

This paper presents a compact 2 × 2 multiple-input multiple-output antenna system designed for 5G smartphones operating in the upper 6 GHz band, and which is to be initially considered as a prototype resembling a user terminal in a channel sounding system. The antenna incorporates a split-ring resonator metamaterial layer, enhancing its gain by at least 1.5 dB across the entire bandwidth without increasing the size of the antenna. The results show a good agreement between the simulations and measurements, achieving a strong isolation, below −18 dB; a low envelope correlation coefficient, lower than 0.025; as well as an efficiency exceeding 75%, making it highly suitable for 5G wireless applications, including both indoor as well as outdoor wireless channel characterization.

Matériaux & Techniques, la revue des matériaux industriels et de leurs techniques de mise en oeuvre