A wideband low-profile radiating G-shaped strip on a flexible substrate is proposed to operate as biomedical antenna for off-body communication. The antenna is designed to produce circular polarization over the frequency range 5–6 GHz to communicate with WiMAX/WLAN antennas. Furthermore, it is designed to produce linear polarization over the frequency range 6–19 GHz for communication with the on-body biosensor antennas. It is shown that an inverted G-shaped strip produces circular polarization (CP) of the opposite sense to that produced by G-shaped strip over the frequency range 5–6 GHz. The antenna design is explained and its performance is investigated through simulation, as well as experimental measurements. This antenna can be viewed as composed of a semicircular strip terminated with a horizontal extension at its lower end and terminated with a small circular patch through a corner-shaped strip extension at its upper end to form the shape of “G” or inverted “G”. The purpose of the corner-shaped extension and the circular patch termination is to match the antenna impedance to 50 $\mathsf{\Omega }$ over the entire frequency band (5–19 GHz) and to improve the circular polarization over the frequency band (5–6 GHz). To be fabricated on only one face of the flexible dielectric substrate, the antenna is fed through a co-planar waveguide (CPW). The antenna and the CPW dimensions are optimized to obtain the most optimal performance regarding the impedance matching bandwidth, 3dB Axial Ratio (AR) bandwidth, radiation efficiency, and maximum gain. The results show that the achieved 3dB-AR bandwidth is 18% (5–6 GHz). Thus, the proposed antenna covers the 5 GHz frequency band of the WiMAX/WLAN applications within its 3dB-AR frequency band. Furthermore, the impedance matching bandwidth is 117% (5–19 GHz) which enables low-power communication with the on-body sensors over this wide range of the frequency. The maximum gain and radiation efficiency are 5.37 dBi and 98%, respectively. The overall antenna dimensions are 25 × 27 × 0.13 mm${}^3$ and the bandwidth-dimension ratio (BDR) is 1733.

In this letter, Laser Induced Graphene (LIG) as a low cost and versatile technique, was utilized to fabricate coplanar waveguide fed polygon monopole antenna on glass substrates. A modified MoS2-graphene heterostructure based antennas were also fabricated and characterized. The formation of the graphene and the successful realization of the hybrid structures were examined and confirmed by several techniques including SEM, Raman and EDX. The conductivity as well as the reliability over large areas were demonstrated for both materials, concluding a significant improvement of MoS2-graphene heterostructure over graphene antenna. Consequently, the two proposed antennas have shown up to 30% enhancement in gain with respect to a reference fabricated copper- based antenna.

Inkjet printing is a low‐cost technique suitable to fabricate flexible electronic devices using solutions of conductive nanoparticles on any type of substrate without material waste as in conventional etching techniques. In this study, a low‐profile wideband coplanar waveguide‐fed monopole antenna operating at 20 GHz is designed and printed using silver nanoparticle ink on polyethylene terephthalate (PET) and on Epson paper substrates. The effects of varying the drop spacing (DS) of the ink on the conductivity of the printed films as well as on the antenna parameters were fully investigated by numerical simulations and by measurements. A conductivity of 1.8 × 10 ⁷ Ω ⁻¹ m ⁻¹ was obtained for the films printed on PET using a DS of 30 µm leading to superior antenna performance with an achieved gain and antenna radiation efficiency of 1.67 dB and 96%, respectively. In addition, the size reduction reached 99%. On the other hand, antennas on Epson paper substrate show an | S ₁₁ | bandwidth <−10 dB extending from 17.18 up to 24.3 GHz, leading to a fractional bandwidth of 34.34%.

Coplanar monopole antennas printed using copper oxide nanoparticles on flexible substrates are characterized in order to study the effect of the ink drop spacing on the antenna parameters. Polyethylene Terephthalate and Epson paper were the chosen flexible substrates, and the antennas were designed to operate at 20 GHz. A maximum conductivity of 2.8 × 10 7 Ω-1 m-1 was obtained for the films printed on Polyethylene Terephthalate using a drop spacing of 20 µm. The corresponding antenna achieved a gain and an efficiency of 1.82 dB and 97.6%, respectively. Experiments showed that smaller drop spacings lead to bulging of the printed lines while the antenna performance worsens for longer ones. At the same drop spacing, antennas printed on Epson paper substrate showed a-10 dB return loss bandwidth which extended from 17.9 GHz to 23.3 GHz, leading to a fractional bandwidth of 26.0%.