Efficient Antenna Design of Inductive Coupled RFID-Systems with High Power Demand

Abstract

<p class="MsoNormal" style="text-align: left; margin: 0cm 0cm 0pt;" align="left"><span class="text"><span style="font-family: ";Arial";,";sans-serif";; font-size: 9pt;">In contrast to pure identification labels, passive inductive coupled RFID transponders with enhanced functionality have an increased power consumption. A nonoptimized antenna design for high power transponders may lead to a poor efficiency and high magnetic field emissions. Therefore, in this work, the energy transmission of inductive coupled systems is investigated, enabling an optimized system design. The RFID system is modeled by network elements in order to optimize the energy transmission. Next to a brief review of different methods for the antenna parameter determination, a new modification of the PEEC method is derived enabling an accelerated and accurate computation of the mutual coupling of the reader and the transponder antenna. Along with the simplification of the transformed transponder impedance and the investigation of the reader matching, consecutive design steps are deduced. The influence of the location-dependent antenna coupling on the energy transmission is characterized. Two case studies are carried out showing a successful transmission of 80mW over a distance of up to 7.6 cm by 275mW reader output power. This system demonstrates an efficient energy supply of a high power transponder while keeping the field emissions low.</span></span><span style="font-family: ";Arial";,";sans-serif";; font-size: 9pt;"></span></p&gt

Interrogation zone determination in HF RFID systems with multiplexed antennas

“…The antenna loop is typically made as a square [8], a rectangle [9], a circle [10] or other polygon [11]. The primary way to enlarge the size of IZ consists in conveying more energy to transponders that are freely deployed and oriented in the space Ω ID .…”

“…However, it is not possible to identify all transponders at any point in the space Ω ID . The most of all these problems are due to the fact that energy can be transferred from the RWD to transponders only on a limited distance [1,[7][8][9][10][11][12][13][14][15][16][17]. Additionally, many parameters and phenomena describing RFID systems have to be considered in a different way than it is in the classical theory valid for typical radio-communication systems.…”

A Review on Wireless Power Transfer in Free Space and Conducting Lossy Media

“…For this system, an output DC voltage of 3.79 V was obtained at the load when the distance between the TC and RC was 5 cm. An inductive coupling system was also proposed in [35] for a radio frequency identification (RFID) system. However, PTE decreases with distance and when misalignment happens.…”

Project and Realization of a Wide-Range High-Frequency RFID Gate Allowing Omnidirectional Detection of Transponders

“…Antennas used for inductively coupled passive RFID systems are designed as loops, allowing the magnetic field component in close field conditions, which is the one that enables the reading of the tag, to be prevalent over the electric field component; therefore the input impedance of a loop is essentially reactive (in particular inductive) [9].…”