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Highly stretchable and shape-controllable three-dimensional antenna fabricated by “ Cut-Transfer-Release ” method

View Article: PubMed Central - PubMed

ABSTRACT

Recent progresses on the Kirigami-inspired method provide a new idea to assemble three-dimensional (3D) functional structures with conventional materials by releasing the prestrained elastomeric substrates. In this paper, highly stretchable serpentine-like antenna is fabricated by a simple and quick “Cut-Transfer-Release” method for assembling stretchable 3D functional structures on an elastomeric substrate with a controlled shape. The mechanical reliability of the serpentine-like 3D stretchable antenna is evaluated by the finite element method and experiments. The antenna shows consistent radio frequency performance with center frequency at 5.6 GHz during stretching up to 200%. The 3D structure is also able to eliminate the hand effect observed commonly in the conventional antenna. This work is expected to spur the applications of novel 3D structures in the stretchable electronics.

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(a) Optical image of 3D serpentine-like antenna on Ecoflex with SMA connector and FR-4 substrate attached (Scale bar: 20 mm); (b) The S11 parameters of the 3D serpentine-like antenna with different applied substrate strain; (c) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in -Z direction; (d) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in Y direction; (e) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in Z direction.
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f4: (a) Optical image of 3D serpentine-like antenna on Ecoflex with SMA connector and FR-4 substrate attached (Scale bar: 20 mm); (b) The S11 parameters of the 3D serpentine-like antenna with different applied substrate strain; (c) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in -Z direction; (d) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in Y direction; (e) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in Z direction.

Mentions: The radio frequency (RF) performance of the 3D antenna with serpentine structure was evaluated by measuring the reflection coefficient (S11). The final assembly of the 3D serpentine-like antenna for measurement is shown in Fig. 4(a) more details in (Fig. S7, Supplementary Information). When an antenna is used in wearable electronics, it is very important to keep the stability of the operation frequency during the deformation of antenna. The S11 parameters of the serpentine-like 3D antenna with different substrate strains εs are plotted in Fig. 4(b). It can be observed that when the 3D serpentine-like antenna was stretched with εs from 0% to 200%, the S11 parameter kept lower than −10 dB from 5.59 GHz to 5.64 GHz, which is an assigned band for the 802.11a/h/j/n/ac wireless network. The radio frequency performance in 5.6 GHz band makes the 3D antenna with the serpentine structure a potential candidate for the antenna of high-speed wireless communication. The resonance frequency of the stretchable 3D antenna in this study can be calculated by , where f is the resonance frequency, l0 is the initial length of antenna, Δl is the incremental length of antenna under uniaxial stretching, εeff is the effective dielectric constant of PI, and k is the correction factor12. According to this equation, the stable S11 parameter during stretching in Fig. 4(b) may be attributed to the structural difference between the 3D antennas we present here and the conventional planar stretchable antennas27282930. For conventional planar stretchable antennas, the large expansion and Poisson’s effect of stretched elastomeric substrate will significantly change the effective length of antenna (l0+Δl), so as to synchronously modulate the resonance frequency12. However, for the 3D structure formed by releasing prestrained substrate, the deformation relies on the out-of-plane mode. This kind of deformation only leads to marginally dimensional change rather than the length change of the serpentine structural unit, as indicated by the strain distribution derived from the FEM results. As the resonant characteristic mode is highly relevant to the overall size of antenna31, the RF performance of serpentine-like 3D antenna will not have obvious change with uniaxial stretching. With the reliable RF performance during deformation, the 3D antenna with a serpentine structure is expected to provide stable RF signal transmittal for the 802.11 high-speed wireless communications in wearable electronics.


Highly stretchable and shape-controllable three-dimensional antenna fabricated by “ Cut-Transfer-Release ” method
(a) Optical image of 3D serpentine-like antenna on Ecoflex with SMA connector and FR-4 substrate attached (Scale bar: 20 mm); (b) The S11 parameters of the 3D serpentine-like antenna with different applied substrate strain; (c) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in -Z direction; (d) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in Y direction; (e) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in Z direction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5304148&req=5

f4: (a) Optical image of 3D serpentine-like antenna on Ecoflex with SMA connector and FR-4 substrate attached (Scale bar: 20 mm); (b) The S11 parameters of the 3D serpentine-like antenna with different applied substrate strain; (c) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in -Z direction; (d) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in Y direction; (e) The S11 parameters of the 3D serpentine-like antenna with different distances to human hand in Z direction.
Mentions: The radio frequency (RF) performance of the 3D antenna with serpentine structure was evaluated by measuring the reflection coefficient (S11). The final assembly of the 3D serpentine-like antenna for measurement is shown in Fig. 4(a) more details in (Fig. S7, Supplementary Information). When an antenna is used in wearable electronics, it is very important to keep the stability of the operation frequency during the deformation of antenna. The S11 parameters of the serpentine-like 3D antenna with different substrate strains εs are plotted in Fig. 4(b). It can be observed that when the 3D serpentine-like antenna was stretched with εs from 0% to 200%, the S11 parameter kept lower than −10 dB from 5.59 GHz to 5.64 GHz, which is an assigned band for the 802.11a/h/j/n/ac wireless network. The radio frequency performance in 5.6 GHz band makes the 3D antenna with the serpentine structure a potential candidate for the antenna of high-speed wireless communication. The resonance frequency of the stretchable 3D antenna in this study can be calculated by , where f is the resonance frequency, l0 is the initial length of antenna, Δl is the incremental length of antenna under uniaxial stretching, εeff is the effective dielectric constant of PI, and k is the correction factor12. According to this equation, the stable S11 parameter during stretching in Fig. 4(b) may be attributed to the structural difference between the 3D antennas we present here and the conventional planar stretchable antennas27282930. For conventional planar stretchable antennas, the large expansion and Poisson’s effect of stretched elastomeric substrate will significantly change the effective length of antenna (l0+Δl), so as to synchronously modulate the resonance frequency12. However, for the 3D structure formed by releasing prestrained substrate, the deformation relies on the out-of-plane mode. This kind of deformation only leads to marginally dimensional change rather than the length change of the serpentine structural unit, as indicated by the strain distribution derived from the FEM results. As the resonant characteristic mode is highly relevant to the overall size of antenna31, the RF performance of serpentine-like 3D antenna will not have obvious change with uniaxial stretching. With the reliable RF performance during deformation, the 3D antenna with a serpentine structure is expected to provide stable RF signal transmittal for the 802.11 high-speed wireless communications in wearable electronics.

View Article: PubMed Central - PubMed

ABSTRACT

Recent progresses on the Kirigami-inspired method provide a new idea to assemble three-dimensional (3D) functional structures with conventional materials by releasing the prestrained elastomeric substrates. In this paper, highly stretchable serpentine-like antenna is fabricated by a simple and quick “Cut-Transfer-Release” method for assembling stretchable 3D functional structures on an elastomeric substrate with a controlled shape. The mechanical reliability of the serpentine-like 3D stretchable antenna is evaluated by the finite element method and experiments. The antenna shows consistent radio frequency performance with center frequency at 5.6 GHz during stretching up to 200%. The 3D structure is also able to eliminate the hand effect observed commonly in the conventional antenna. This work is expected to spur the applications of novel 3D structures in the stretchable electronics.

No MeSH data available.


Related in: MedlinePlus