Experimental Study on Brush-Painted Passive RFID-Based Humidity Sensors Embedded into Plywood Structures

Abstract

The integration of electronics and wood is an interesting research area due to the increasing interest to add functionality into various wooden products. The passive RFID-based humidity sensor tag prototype, presented in this paper, is fabricated directly on plywood substrate to be embedded into wooden structures, by using brush-painting and photonic sintering of cost-effective silver ink. To the best of our knowledge, this is the first demonstration of brush-painted antennas as sensor elements. The developed sensor tag is fully passive and small in size, meaning it can be permanently enclosed into wooden structures. In addition, the sensor tag has all the functionalities of an ordinary passive UHF RFID tag, and a peak read range of about 10 meters. The sensor performance was evaluated in normal room conditions, after two 100% relative humidity tests, and after drying in normal room conditions for 9 days. According to the results, the fabricated UHF RFID-based humidity sensor tags have a great potential to be utilized in humidity sensing applications, and also in normal automatic identification and supply chain control of various wooden products. In addition, the first results of more cost-effective brush-painted copper UHF RFID tags on plywood substrate are presented.

The potential of paper-based diagnostics to meet the ASSURED criteria

“…RFID is well-suited to paper-based diagnostics as the tag antennas are printable and paper is well-suited for ultra-high frequency (UHF) and microwave applications. 133 Printing of antennas 133–137 and specifically RFID tags 138–143 on to low-cost paper and cardboard substrates has been investigated using both inkjet and screen printing techniques ( Fig. 9B ).…”

A Review on Materials and Technologies for Organic Large‐Area Electronics

“…Copper and silver inks were used to produce the antennas and demanded sintering, thus, to avoid the use of high temperatures (incompatible with both substrates), photonic sintering at ambient conditions was performed. [ 299 ] After sintering, an IC chip was integrated onto the structure, which enabled wireless communication. However, the flexibility of the wood substrate was limited.…”

“…In a low-cost and additive deposition approach, Sipilä et al resorted to a brush-painting and stencil method to manufacture RFID tags on top of large-scale wood and cardboard substrates. [299] The stencil was a 50 µm thick PI film and one single layer of ink was deposited. The wood substrate was 4 mm thick composed of 3 layers, whereas the cardboard was a normal packaging material.…”

A Bending Passive RFID Tag as a Sensor for High-Temperature Exposure

“…It can be utilized to perform as wireless sensors, which are easy to manufacture, low cost, and efficient [3,[6][7][8]. Adding sensing capabilities to passive RFID tags has been widely studied [9][10][11][12][13][14], and by tracking changes in the tags' backscattered signals, passive UHF RFID tags have been used for sensing without external sensors, such as strain [15][16][17][18][19], moisture [20][21][22][23][24], pressure [25,26], and especially temperature sensors [27][28][29].…”