Wearable Button-Like Dual-Band Central Antenna for Wireless Bodyarea Networks

Abstract

A novel dual-band conical-helix/monopole antenna is proposed to operate as an on-body central antenna for Wireless Body Area Network (WBAN). The proposed antenna communicates in three ways: (i) off-body communication through its end-fire radiation with the ceil-mounted WiMax antenna at 5.8 GHz, (ii) on-body communication through its broadside radiation with the on-skin biosensor antennas at 3.0 GHz, and (iii) in-body communication with the in-body (implanted) biosensor antennas at 3.0 GHz. The characteristics of the proposed antenna are investigated through electromagnetic simulation and experimental measurements where a prototype of this antenna is fabricated for this purpose. The antenna is matched with 50 Ω coaxial feeder over the dual frequency bands, mounted on a copper circular disc, and covered with a very thin dielectric radom for mechanical protection. Such an antenna covered by the radom is shaped like a hemispherical button that can be attached to patient clothes and, hence, it can be considered as a wearable antenna. The radiation patterns obtained by experimental measurements show good agreement with those obtained by the CST R simulator and are shown to be appropriate for communication with the ceil-mounted WiMAX antenna and the biosensor antennas at 5.8 GHz and 3.0 GHz, respectively. The distribution of the microwave power density near the body surface is evaluated by simulation and experimental measurements to ensure the realization of the electromagnetic exposure safety limits. The Specific Absorption Rate (SAR) distribution inside the human tissues of concern is evaluated showing a safe level of electromagnetic exposure. Quantitative assessment of the WBAN communication system performance is achieved when the proposed antenna is employed as an on-body central antenna for the WBAN. Thanks to the optimized design of the proposed antenna the Bit-Error-Rate (BER) is shown to be very low even when the input power fed to the antenna is only 1 mW.

Dual‐band dual‐mode monopole/spiral central antenna for WBAN applications

“…The external diameter of the spiral is $${D}_{S}=12\,\text{mm}$$; the number of turns is $$N=3$$. The effect of the human body is included in the electromagnetic simulation using three‐layers model 14 . The dielectric constant and the conductivity of the used tissues are shown in Table 1 at 2.45 and 5.8 GHz 14 …”

“…The effect of the human body is included in the electromagnetic simulation using three‐layers model 14 . The dielectric constant and the conductivity of the used tissues are shown in Table 1 at 2.45 and 5.8 GHz 14 …”

“…The effect of the human body is included in the electromagnetic simulation using three-layers model. 14 The dielectric constant and the conductivity of the used tissues are shown in Table 1 at 2.45 and 5.8 GHz. 14 F I G U R E 1 (A) The fabricated monopole/spiral antenna compared to a standard coin of size 1 inch, (B) Antenna covered with a radom and attached to clothes as a button, and (C) CST® model of the antenna mounted on the three layers model.…”

Flexible Antenna with Circular/Linear Polarization for Wideband Biomedical Wireless Communication

“…To minimize the power required for communication within the nodes of the WBAN, the ultra-wideband (UWB) antennas are preferred to narrowband antennas for their low-power spectral density that is restricted to 41.3 dBm/MHz [8,9]. For this reason, the proposed G-shaped antenna is designed to operate in the "on-body" mode with linear polarization over the wide frequency band (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). In this mode, the central antenna operates with linear polarization to communicate with the biosensor antennas for collecting biotelemetry data.…”

“…As shown in Figure 2, the WiMAX/WLAN antenna that may have arbitrary polarization (vertical or horizontal). To reduce the power loss caused by misalignment with the WiMAX/WLAN antenna, the G-shaped antenna is designed to produce circular polarization while operating in the "off-body" mode (5-6 GHz) and linear polarization while operating in the "on-body" mode (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19).…”