A General Strategy for Stretchable Microwave Antenna Systems using Serpentine Mesh Layouts

Abstract

Wireless functionality is essential for the implementation of wearable systems, but its adaptation in stretchable electronic systems has had limited success. In this paper, the electromagnetic properties of stretchable serpentine mesh-based systems is studied, and this general strategy is used to produce high-performance stretchable microwave systems. Stretchable mechanics are enabled by converting solid metallic sections in conventional systems to subwavelength-scale serpentine meshes, followed by bonding to an elastomeric substrate. Compared to prior implementations of serpentine meshes in microwave systems, this conversion process is extended to arbitrary planar layouts, including those containing curvilinear shapes. A detailed theoretical analysis is also performed and a natural tradeoff is quantified between the stretching mechanics and microwave performance of these systems. To explore the translation of these concepts from theory to experiment, two types of stretchable microwave devices are fabricated and characterized: a stretchable far-field dipole antenna for communications and a stretchable midfield phased surface for the wireless powering of biomedical implanted devices.

Stretchable and Directly Patternable Double-Layer Structure Electrodes with Complete Coverage

“…Because the deformation of the antenna led to an increase in its inductance and capacitance, which in turn decreased the resonant frequency. Such a shift in the resonant frequency is in good agreement with a previous study . The resonant frequency barely shifted to <0.018 GHz after 1 000 stretching cycles at 30% (Figure C).…”

“…Such a shift in the resonant frequency is in good agreement with a previous study. 49 The resonant frequency barely shifted to <0.018 GHz after 1 000 stretching cycles at 30% (Figure 4C). The far-field radiation pattern of the antenna was characterized by unstretched (0%) and stretched (30%) conditions at their resonant frequencies in an anechoic chamber (Figure 4D).…”

Standalone stretchable RF systems based on asymmetric 3D microstrip antennas with on-body wireless communication and energy harvesting

“…Compared with a nearly 50% increase from 1.57 to 2.34 dB for the "Sym_1:1" antenna, the peak gain increase of 9% (from 3.52 to 3.83) and 20% (from 3.09 to 3.72) is smaller for the "Asy_1:2" and "Asy_2:1" microstrip antennas (Figure S10). The increased peak gain possibly arises from the densified meshed networks upon stretching, which is consistent with previously reported results [32,45].…”

Stretchable Antenna Arrays‐Enabled Multi‐Target Balloon Wireless Communication System

“…Therefore, there exists a trade‐off between mechanical stretchability and microwave power dissipation in serpentine the microwave devices. [ 27 ] In this design, metal sections are subdivided into a subwavelength‐scale unit cell grid, forming a serpentine structure to achieve the stretchability of the device. The arc angle of the serpentine mesh is related to the mechanical stretch of the device, and the relationship between the arc angle and stretch is analyzed through mechanical simulations.…”

“…It should be noted that replacing solid metal with serpentine square lattices on the ground will result in redshift of the resonant frequency of the patch, because the serpentine lattice structure increases the effective wavelength in the current path. [ 27,64 ] Therefore, the initial solid patch should be designed at a higher frequency to achieve the desired working frequency of the stretchable antenna. [ 65 ]…”