Flexible force sensitive frequency reconfigurable antenna base on stretchable conductive fabric

Abstract

With the development of wireless technology and flexible electronics, flexible frequency reconfigurable antennas have been directly used as sensors to detect mechanical signals. As an important frequency reconfigurable antenna, microstrip antenna has been widely studied in the field of flexible and flexible electronics in recent years. However, the stretchability of microstrip antennas usually comes at the cost of reducing the conductivity of the radiated conductor. Here, we report a flexible force sensitive frequency reconfigurable microstrip antenna, which fabricated by silver fiber conductive fabric with a double-wire braided structure. In order to increase the detection of pressure, an elastic dielectric layer with a microhemispheric array was introduced into the microstrip antenna to extend the frequency band width of the reconfigurable antenna. The relative frequency of the antenna varied from 0~-12.9%, and the sensing sensitivity was -1.9 kPa-1. As potential applications, we demonstrate the use of a flexible frequency reconfigurable antenna base on stretchable conductive fabric as a strain sensor capable of measuring bending angle and movements of a human finger. The change in the resonance frequency with the externally applied tensile strain in this antenna design has a sensitivity of 3.448, manifesting a 4.19- and a 13.79-fold increase of sensitivity when compared to those in previous reports that used arched or both-planes serpentine rectangular microstrip antenna. This is of great significance for the application of wearable antenna in wireless mechanical sensing technology.

Assessment of the Robustness of Flexible Antennas to Complex Deformations

“…Overall, comparing Figs. (16)(17)(18)(19)(20)(21) it can be concluded that when concave deformations are considered the spherical deformation is better correlated with the cylindrical bending along antenna length when the impact on the resonant frequency is considered but better correlated to the cylindrical bending along the width of antenna when fractional bandwidth is considered. For the case of convex deformations, the spherical deformation is better correlated to the cylindrical bending along the width of antenna when the impact on both the resonant frequency and the bandwidth is considered.…”

“…Integration of antennas into clothing means that the antennas will be affected by the dynamics of the human body that can cause a variety of deformations [15][16][17][18][19] which in turn can degrade the overall system's performance and present a challenging design task for wearable antenna design.…”

“…For example, F. A. Author is with the antennas are bent in situ along a cylindrical plane, primarily using experimental measurements [2,3,[19][20][21][22][23][24] and less frequently using commercial software such as Ansys and CST [21,22,[24][25][26].…”

A Flexible Bi-Stable Composite Antenna with Reconfigurable Performance and Light-Responsive Behavior

“…According to the existing reports, it is known that the bending angle of antennas has a significant impact on their working frequency and pattern [ 22 ]. Hu et al [ 23 ] prepared the reconfigurable antenna by layering, which laid the foundation for the feasibility of the research in this paper.…”

A transparent water-based metamaterial broadband absorber with a tunable absorption band

“…However, most of the MMAs that have been designed so far have a fixed operating bandwidth, which means that they can only work in a limited area. For example, absorbers designed in the X-band (8-12 GHz) and Kuband (12-18 GHz) can be used as absorbing microwave radars [29][30][31] to reduce the RCS of a target and reduce the chance of detection by the enemy, while millimeter wave radars operating in the Ka (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) band are also being used on the battlefield as detection technology continues to develop [32]. Designed in the C-band (4-8 GHz) or Ku-band MMAs can be used in satellite communications [33][34][35], but with the increasing depletion of satellite orbit resources in C and Ku-band, satellite communications in Ka-band have become a latecomer [36].…”