Study of a flexible low profile tunable dipole antenna using barium strontium titanate varactors

Abstract

In this paper a flexible low profile dipole antenna using a frequency selective surface (FSS) with interdigital barium strontium titanate (BST) varactor-tuned unit cells is presented. The varactor chips were placed only along one dimension of the FSS to avoid the use of vias and simplify the DC bias network. The antenna uses overlapping metallic plates that resemble fish scales as a ground plane to improve the flexibility of the multi-material stack structure. The measured data of the antenna demonstrate tunability from 2.42 GHz to 2.66 GHz and 1.3 dB gain drop when using overlapping metallic plates instead of continuous ground plane. The total antenna thickness is approximately lambda/24. Index Terms-Flexible antennas, varactor-tuned high impedance surfaces, chip capacitors, BST, Young's module.I.

Flexible Antennas: A Review

“…Different liquid metals such as mercury, carbon nanotubes (CNT), Galinstan, gallium indium (GaIn), and eutectic gallium indium (EGaIn) are injected into the channel to form the antenna [ 248 , 249 , 250 ]. Besides PDMS, EcoFlex silicone rubber [ 251 ] and thermoplastic polyurethane (TPU) based NinjaFlex [ 114 ] are also used as an elastomer for creating microfluidic channel, and are usually 3-D printed to realize a specific pattern. Another challenge of designing flexible antennas is identifying suitable conducting materials that sustain different bending and twisting conditions and have reasonable resistance value as not to affect the antenna radiation efficiency.…”

Recent Development of Flexible and Stretchable Antennas for Bio-Integrated Electronics

“…The high-frequency operation of the antenna is also associated with additional benefits such as high-speed communication and low power consumption. As an alternative to operating at the high frequency, the other approach for downsizing the antenna is to use the substrate material with a high dielectric constant [104,105]. The typical dielectric constant of the elastomeric substrate such as silicone is between 2.5 to 3 in the GHz range [103].…”

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