Approach to Fabricate Rigid Substrate for 2.4 GHz Inverted-F Antenna Using a Room Temperature Curable Dielectric Ink on Photo and Nanopaper

Abstract

The effect of a room temperature curable dielectric ink (ZrSiO 4 ) printed on commercial photo paper and prepared nanopaper on the dielectric properties at 2.4 GHz are studied.In both cases, the dielectric layer decreased the relative permittivity and dielectric loss and made the flexible substrates rigid. For the nanopaper, the permittivity decreased from 4.7 to 3.57 and the loss value from 0.12 to 0.04. The measured decreases for the photo paper were from 3.12 to 2.61 and from 0.09 to 0.05, respectively. In the performance of the simulated and fabricated inverted-F antennas (IFA), the effect of the dielectric layer could be observed in the decrease of its frequency with about 130Marked Manuscript 2 MHz mainly due to the thicker substrate. The measured total efficiency and gain were 83% and 3.4 dB. The proposed approach could be in the future used for further development of the antenna by modification of the dielectric ink with different additives. KeywordsRoom temperature curable dielectric ink; low loss tangent; Inverted F Antenna (IFA); WLAN; printing; paper; Nanocellulose IntroductionWireless communication wearable devices are becoming popular in many emerging applications. Modern wearable applications like smart watches use wireless technologies like Bluetooth, Wi-Fi, long-term evolution (LTE) and global positioning system (GPS), thus requiring integration of an antenna into the measuring unit. The design of antennas suitable for wrist applications is a challenging task due to the requirements of the compact and especially thin design and low manufacturing costs [1]. The inverted-F antenna (IFA) structures are widely used in wearable applications because of their simple and flexible design, low fabrication cost, and reliable performance [2, 3]. On the other hand, printable electronics can produce very thin, lowcost, and lightweight structures. It is thus clear that fabrication of antennas using printable electronics would offer an optimal solution to realizing flat, inexpensive antennas.Paper is a desired candidate for a low-cost substrate for RF printed electronic applications. It has a low surface profile and, with an appropriate coating, it is suitable 3 for fast printing processes such as direct write methodologies instead of the traditional metal etching techniques. Conductive inkjet printed antennas on flexible, low-cost paper-based substrates have been reported for RFID (Radio-frequency Identification) and WSN (Wireless Sensor Network) applications [4]. For printed antennas, an interesting new option is paper based on nanocellulose (denoted here as nanopaper), which has a densely packed, layered structure allowing highly conductive and sensitive antenna lines at higher frequencies. However, the dielectric properties of common and nanopaper depend on manufacturing route and used raw materials [5][6][7][8]. Thus, the dielectric properties such as dielectric constant (ε r ) and loss tangent (tanδ) have to be characterized before designing the high-frequency structures [5,[9][10][11]]. However, one main ...

Flexible high dielectric thin films based on cellulose nanofibrils and acid oxidized multi-walled carbon nanotubes

“…Among them are so high dielectric materials, which are in hugely demand in high-tech applications such as foldable touch screens, antennae, biosensors, inverters, organic transistors, and hybrid electrical vehicles. [1][2][3] Materials with a high dielectric constant can considerably increase the energy density and power, accelerate the charge/discharge speed, and reduce the size of devices. So high dielectric materials are more preferred in portable, foldable and wearable electronic devices.…”