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The use of the natural materials instead of conventional materials as electromagnetic absorbers promotes environmental sustainability, cost-effectiveness, and ease of accessibility. Furthermore, these materials may also be designed as absorbers and as reinforcements in building materials in a lightweight form. The absorbing ability of composite materials can be customized based on the chosen fillers. Specifically, magnetic and dielectric fillers can be incorporated to improve the absorption of a composite material compared to traditional materials. This work aims to review recent developments of electromagnetic absorbers enabled by nanocomposites, metamaterial and metasurface-based, as well as green composite alternatives. First, the background concepts of electromagnetic wave absorption and reflection will be presented, followed by the assessment techniques in determining electromagnetic properties of absorbing materials. Next, the state-of-the-art absorbers utilizing different materials will be presented and their performances are compared. This review concludes with a special focus on the future perspective of the potential of metamaterial based nanocellulose composites as ultrathin and broadband electromagnetic absorbers.

This paper presents the assessment of short-term wireless body area network (WBAN) exposure, which is operated at the industrial, scientific, and medical (ISM) band (2.45 GHz) in the vicinity of the human body. The experiment utilizes two popular textile antenna topologies, a planar monopole and a patch antenna as the radiating sources. The objective of this experiment is to investigate whether the exposure from WBAN may influence the physiological parameters (body temperature, blood pressure, and heart rate) and the well-being of the wearer. Counter-balanced, crossover, and the single-blind method was applied in the experimental setup. $P$ -value is the probability value, under the assumption of no effect or no difference (the null hypothesis) of obtaining a result equal to or more extreme than what was actually observed. If $P , it indicates that $P$ -value will be less than the level of significance. Thus, the null hypothesis (no effect or no difference) can be rejected, and it can be concluded that there exist effects to the respondents. The results showed that there is statistically no significant difference between the active exposure and the Sham (no exposure) which may affect the physiological parameters and well-being of the wearers, with $P>0.05$ , which failed to reject the null hypothesis (no effect).