Flexible low dielectric permittivity paper as a disposable substrate for centimeter wave patch antennas

<h2>Summary</h2> For mid-to-low-end and disposable wireless transmission devices, paper-based low dielectric substrates are cost-effective and environmentally friendly compared to traditional petroleum-based plastics such as polyimides. In this work, we introduce (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-mediated oxidation technology into commercial copy paper to achieve <i>in situ</i> growth of zeolitic imidazolate framework (ZIF-67) while increasing porosity. Through impregnation technology, ethyl cellulose and h-BN are combined to improve the water resistance (water contact angle: 122°), thermal conductivity (in-plane thermal conductivity: 13.55 W m⁻¹ K⁻¹), and antibacterial properties of the paper. The dielectric permittivity of modified paper is about 3, which exhibits excellent potential as a substrate for centimeter wave patch antennas. After verification, our developed paper oxidation technology is reliable and effective for various cellulose-based papers. This paper provides a low-cost and low-energy approach for the construction of cellulose-based porous structures, which promote the development and application of green materials and alleviate the serious global problem of electronic waste pollution.