title: Conformal Pad-Printing Electrically Conductive Composites onto Thermoplastic Hemispheres: Toward Sustainable Fabrication of 3-Cents Volumetric Electrically Small Antennas.
abstract: Electrically small antennas (ESAs) are becoming one of the key components in the compact wireless devices for telecommunications, defence, and aerospace systems, especially for the spherical one whose geometric layout is more closely approaching Chu's limit, thus yielding significant bandwidth improvements relative to the linear and planar counterparts. Yet broad applications of the volumetric ESAs are still hindered since the low cost fabrication has remained a tremendous challenge. Here we report a state-of-the-art technology to transfer electrically conductive composites (ECCs) from a planar mould to a volumetric thermoplastic substrate by using pad-printing technology without pattern distortion, benefit from the excellent properties of the ECCs as well as the printing-calibration method that we developed. The antenna samples prepared in this way meet the stringent requirement of an ESA (ka is as low as 0.32 and the antenna efficiency is as high as 57%), suggesting that volumetric electronic components i.e. the antennas can be produced in such a simple, green, and cost-effective way. This work can be of interest for the development of studies on green and high performance wireless communication devices.
authors: Division of Energy and Environment, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors: Haoyi
authors: H
authors: Wu
authors: Division of Energy and Environment, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors: Sum Wai
authors: SW
authors: Chiang
authors: Division of Energy and Environment, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors: Cheng
authors: C
authors: Yang
authors: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America.
authors: Ziyin
authors: Z
authors: Lin
authors: Division of Energy and Environment, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors: Jingping
authors: J
authors: Liu
authors: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America.
authors: Kyoung-Sik
authors: KS
authors: Moon
authors: Division of Energy and Environment, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China; State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing, China.
authors: Feiyu
authors: F
authors: Kang
authors: Division of Energy and Environment, Graduate School at Shenzhen, Tsinghua University, Xili University Town, Shenzhen City, China.
authors: Bo
authors: B
authors: Li
authors: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America; Department of Electronic Engineering, Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
authors: Ching Ping
authors: CP
authors: Wong
mesh_terms: D004553:Electric Conductivity; D004581:Electronics / Q000191:economics / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D013499:Surface Properties; D059015:Wireless Technology / Q000191:economics / Q000295:instrumentation*