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Abstract-This paper proposes wearable electronic modules on textile, suitable for garment integration, based on antennas magnetically coupled to the active circuitry. The coupling mechanism is based on a heterogeneous transformer with the primary and secondary windings implemented in the antenna and in the circuitry substrate (hybrid or monolithic), respectively. The proposed coupling topology avoids galvanic contacts between the antenna and the active circuitry, allowing for interconnecting the antenna by a mere placing and gluing process. Bonding and soldering processes, often critical for textile materials are thus avoided. The proposed innovation, mitigating the industrial realization constraints posed by textile implementation of active antennas and RFID tags, should unsurprisingly enable and foster industrial developments of garment RFID, wearable electronics and body-centric communications systems. A patch antenna with transformer based on textile materials and operating in the frequency band 2.4-2.4835 GHz is designed, realized and measured.

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This paper summarizes the most important technologies, concurrently participating to build the technological platform needed for a realistic implementation of the Internet of Things (IoT) paradigm. At the present state of the evolution of IoT, these technologies are mostly: Radio Frequency IDentification (RFID), Green Electronics (GE), Wireless Power Transfer (WPT) and Energy Harvesting (EH). This contribution briefly explains the reason for that, and shows a collection of scientific contributions which can be seen as examples. The deep description of the proposed systems can be found in the relative referenced papers.

Abstract-This paper deals with a low-cost method for the assembly of flexible substrate antennas and UHF RF identification silicon (Si) chips. Such a method exploits a magnetic coupling mechanism, thus not requiring for galvanic contacts between the Si chip and antenna itself. The magnetic coupling is established by a planar transformer, the primary and secondary windings of which are implemented on flexible substrate and Si chip, respectively. As a result, the Si chip can be assembled on the antenna with a mere placing and gluing process. First, the idea has been validated by theory. Electromagnetic simulations of a square heterogeneous transformer (1.0-mm side) show a maximum available power gain (MAG) of 0.4 dB at 868 MHz. In addition, the heterogeneous transformer is also quite tolerant with respect to misalignment between primary and secondary. An offset error of 150 m reduces the MAG to 0.5 dB. A sub-optimal matching strategy, exploiting a simple on-chip capacitor, is then developed for antennas with 50-input impedances. Finally, the idea has been experimentally validated exploiting printed circuit board (PCB) prototypes. A PCB transformer (1.5-mm side) and a transformer rectifier (two-diode Dickson multiplier) have been fabricated and tested. Measurements indicates a MAG of 0.3 dB at 868 MHz for the transformer and the capability of the developed rectifier to supply a 220-k load at 1.5 V with a 2-dBm input power.