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An ultrathin, compact, and highly efficient antenna based on the $\Pi $ -section composite right/left-handed (CRLH) methodology is presented. It operates at 2.45 GHz of the Industrial, Scientific and Medical (ISM) band with a physical size of 25 mm $\times25$ mm, a realized gain of 2.34 dBi, and a total efficiency of 87% in free space. Nevertheless, to maintain resonance at 2.45 GHz with body-loading scenarios, a high separation was required, leading to an overall large size. To circumvent that, an all-textile $2 \times 2$ artificial magnetic conductor (AMC) array was placed in-between the antenna and the human body. In free space, the low-profile integrated design exhibited a gain of 7.63 dBi (enhancement of 5.29 dBi) and total efficiency of 96.4%. The integrated design achieved a gain and total efficiency enhancements by 14.88 dBi and 72.4%, respectively, as well as, lower specific absorption rate (SAR) levels, in comparison with the CRLH antenna alone, for human loading cases. Results are achieved through circuit model and full-wave electromagnetic simulations. In addition, the CRLH antenna and AMC array structure were fabricated and measurements were undertaken, which agreed well with the simulated ones. Therefore, the integrated design is highly suggested to be recognized in wireless body area network (WBAN) and medical applications. [ABSTRACT FROM AUTHOR]

A dual-band, low profile, high gain, and low specific absorption rate (SAR) triangular slotted monopole antenna backed with a $4\times 4$ artificial magnetic conductor (AMC) array is presented for wireless body area network (WBAN) applications. The antenna is printed on a Rogers ULTRALAM 3850 substrate, whereas the AMC array is printed on a RO3003 substrate. The design operates at 3.5 GHz, for WiMAX wireless applications, and at 5.8 GHz for the ISM Band. The proposed antenna preserved the dual-band resonance and exhibited acceptable gain and SAR at a separation of 15 mm from the human body model. To reduce such separation and achieve enhancements to gain and SAR, an AMC array was utilized. In free space, gain enhancements by 6.8 and 3.7 dBi were achieved at both frequencies, respectively. Furthermore, over a gap of 1 mm from the human body, gain enhancements by 23.3 and 13.9 dBi were achieved at both frequencies, respectively. In addition, SAR reductions by almost 99% were attained. The antenna was fabricated and measured where a very good agreement was observed between simulated and measured results, with and without the incorporated AMC array. With such results, the proposed design can be highly recommended for wearable medical applications, specifically for diabetic patients. [ABSTRACT FROM AUTHOR]