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A compact ultrawideband (UWB) antenna based on a hexagonal split-ring resonator (HSRR) is presented in this paper for sensing the pH factor. The modified HSRR is a new concept regarding the conventional square split-ring resonator (SSRR). Two HSRRs are interconnected with a strip line and a split in one HSRR is introduced to increase the electrical length and coupling effect. The presented UWB antenna consists of three unit cells on top of the radiating patch element. This combination of UWB antenna and HSRR gives double-negative characteristics which increase the sensitivity of the UWB antenna for the pH sensor. The proposed ultrawideband antenna metamaterial sensor was designed and fabricated on FR-4 substrate. The electrical length of the proposed metamaterial antenna sensor is 0.238 × 0.194 × 0.016 λ, where λ is the lowest frequency of 3 GHz. The fractional bandwidth and bandwidth dimension ratio were achieved with the metamaterial-inspired antenna as 146.91% and 3183.05, respectively. The operating frequency of this antenna sensor covers the bandwidth of 17 GHz, starting from 3 to 20 GHz with a realized gain of 3.88 dB. The proposed HSRR-based ultrawideband antenna sensor is found to reach high gain and bandwidth while maintaining the smallest electrical size, a highly desired property for pH-sensing applications.

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E-medicine is a process to provide health care services to people using the Internet or any networking technology. In this Letter, a new idea is proposed to model the physical structure of the e-medicine system to better provide offline health care services. Smart cards are used to authenticate the user singly. A very unique technique is also suggested to verify the card owner's identity and to embed secret data to the card while providing patients' reports either at booths or at the e-medicine server system. The simulation results of card authentication and embedding procedure justify the proposed implementation.

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In this paper a compact microstrip patch antenna designed for the unlicensed 60 GHz millimeter-wave band applications is presented and discussed in details. The proposed antenna consists of a rectangular radiating patch with an embedded U-shape slot inside, and excited by the coaxial probe feeding technique. A wide range of parametric studies has been performed on the patch size, feeding positions and U-slot dimensions and the antenna is optimized for the best possible results. The proposed antenna configuration achieved a wide bandwidth of 15.4 GHz (25.69 %) covering the frequency range from 52.20 to 67.70 GHz. The lowest return loss of the antenna is -41.2 dB and the maximum gain obtained is 9.52 dB at the 60 GHz resonance frequency. Considering the size, bandwidth, and gain, this microstrip antenna can be a suitable candidate for the 60 GHz wireless applications for short range high speed communications.

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