Nr.StatusDescriptionFiguresFurther Information
18 oral presentation,
RF Harvesting at 2.4 GHz for Scattering between Battery-less Transponder and Mobile Telephones

This work studies RF (radio frequency) harvesting of electromagnetic energy from intentionally generated wireless RF signals in the 2.4 GHz ISM band as power supply for a battery-less back-scattering transponder. According to our implementation, a first mobile telephone transmits a quasi-continuous Bluetooth advertizing signal and the transponder scatters and modulates this signal such that it is receivable by a Bluetooth receiver of a further mobile telephone. The scattering process includes 4 MHz frequency translation and frequency shift keying for information transmission. The modulation process is controlled by a low energy micro-controller, which obtains its operational energy from a RF harvesting circuit that accumulates energy from the incident RF signals. The low energy transfer of Bluetooth signals motivates the present feasibility study, which proposes a supplement of WLAN signals as additional source of energy for the battery-less transponder. The present study includes examining alternative WLAN modes: "tethering", "WiFi direct" and "ad hoc" and concludes that an Android specific form of WLAN tethering shows the most promising potential for our scattering application, which is based on regular, unmodified mobile telephones. Thus, by additionally using WLAN signals, we achieved a significant range improvement of the wireless energy transfer from the transmitting mobile telephone to the battery-less transponder, which encourages further endeavors in this direction.
Delhi, India,
2021 (virtual)
15 oral presentation,
Harvesting for Scattering Bluetooth-Signals between Battery-less Transponder and Mobile Telephones

The present work studies the feasibility of using the BLE transmitter of a further mobile telephone for providing the incident RF signal. This approach requires dealing with the intermittent nature of practical wireless communication, which motivates the use of the BLE Standard version 5.0, namely the extended advertizing messages and their periodic retransmissions. Our experiments involve a specifically designed code sequence, which generates a quasi-continuous wave signal of approx. 2 ms duration, which provides the basis for the transponder’s scattering process.
Wireless Power Transfer Conference (WPTC),
Seoul, South Korea, 2020 (virtual)
IEEE Publication
13 oral presentation,
Harvesting for Scattering Modulated RF-Signals Receivable by Mobile Telephones

We operate a micro-controller (MCU) of a transponder tag by using energy from an RF harvesting circuit, which accumulates energy of an incident CW signal. The MCU uses its internal asynchronous RC oscillator and counter as well as an external 1 MHz crystal, which provides a time base for digitally changing the frequency of the internal oscillator in dependency of the information to be transmitted. Thus, this work combines precise scattering technology with RF energy harvesting. The transponder tag achieves an active power consumption of 9.2 mW.
Wireless Power Week (WPW)
London, UK, 2019
IEEE Publication
10 poster presentation,
Harvesting for Scattering RF-Signals receivable by Mobile Telephones

This work combines RF harvesting and scattering technology, which reflects and modulates an incident continuous wave signal such that the scattered signal is receivable by a Bluetooth Low Energy (BLE) receiver of a mobile telephone. We achieved unidirectional BLE advertising by combining scattering technology and energy harvesting and thus showed the feasibility of wireless communication from a battery-less RF transponder to a regular mobile telephone.
Wireless Power Transfer Conference (WPTC)
Montreal, Canada, 2018
IEEE Publication
07 poster presentation,
Energy Harvesting in EM Fields

Evaluation of electromagnetic energy and design of a suitable harvesting prototype. The project involved evaluating the potential of energy harvesting in different wireless communication environments, incl. personal cell phones, as well as implementing a harvesting circuit by specifically designing antenna, matching circuit and voltage multiplier. The overall prototype arrangement achieved energy harvesting at –53 dBm/cm2 (–33 dBm/harvester), thus an improvement over known reference circuits. The wirelessly harvested power was sufficient to operate low energy devices such as sensors and microcontrollers (pocket calculator).

Project at FHO-HSR (University of Applied Sciences), Rapperswil, Switzerland
with idp invent ag as project partner
05 Patents and Divisional Application for Sale/License Transponder tag that is operable by a mobile telephone,
portable object, mobile telephone, and corresponding methods

Transponder Tag for receiving wireless signals at a frequency of a local wireless network (ISM radioband), configured to use the energy of these signals for transmitting tag information to a mobile telephone via a short-range RFID connection. This is particularly useful for numerous short distance applications, e.g. for obtaining a quick confirmation that all needed personnel belongings (keys, medical box etc.) are "on board" when leaving home/office.
01 Patents for Sale/License Method of operating an RFID-enabled mobile telephone,
mobile telephone, remote unit and application program product

RFID-enabled Mobile Telephone for quickly and conveniently checking the nearby presence of correspondingly tagged portable objects (keys, medicine box etc.), e.g. before leaving home or office, and a wristwatch for remotely controlling such a telephone