Multifunctional coil technique for alignment-agnostic and Rx coil size-insensitive efficiency enhancement for wireless power transfer applications.

This paper presents a multifunctional coil technique to enhance the transfer efficiency of an inductively-coupled wireless power transfer (WPT) system, regardless of the alignment condition and size ratio between the transmitter (Tx) and receiver (Rx) coils. The technique incorporates an auxiliary coil on the Tx side, where current is induced through coupling from the primary coil. Since the Tx coil consists of two coils, transmission to the Rx occurs through the coil with the higher coupling coefficient, determined by the misalignment state.

Passive Wireless Sensor Utilizing an Interdigital Capacitor for Ongoing Monitoring of Glucose Concentration.

The wireless glucose sensor represents a major step forward in continuous glucose monitoring. With its innovative interdigital capacitor and inductor combination, the sensor works without active components and can measure glucose levels by detecting changes in reflection magnitude of the surrounding environment. Experimental results validated the proposed passive sensor's capability in detecting glucose concentration in aqueous solution, demonstrating a linear relationship between reflection magnitude and glucose concentration ranging from 0 to 500 mg/dL with a sensitivity of 3×10 dB/(mg/dL).

On Encapsulated Dielectric Barrier Discharge Plasma Sources for Radar Cross Section Reduction in Mobile Environments.

This paper deals with the practical application of Radar Cross Section (RCS) reduction technology using plasma. Although various plasma application technologies for RCS reduction have been studied, there are still many issues to be addressed for practical implementation. In order to achieve actual application, the discharge should be sustained regardless of the external environment of the aircraft.

Compensation of Heat Effect in Dielectric Barrier Discharge (DBD) Plasma System for Radar Cross-Section (RCS) Reduction.

In this study, the problems encountered in radar cross-section (RCS) measurement experiments utilizing a dielectric barrier discharge (DBD) plasma system are examined and an effective solution is proposed. A DBD plasma system generates heat due to the high bias voltage required for plasma generation. The thermal-induced structural deformation of the DBD structure caused by this high voltage and its impact on RCS measurements are analyzed.

Dual-Band Branch-Line Coupler Based on Crossed Lines for Arbitrary Power-Split Ratios.

Dual-band branch-line couplers with arbitrary power-split ratios are presented. The use of crossed lines at the center of the dual-band coupler enables it to independently provide different power-split ratios to the two bands. Additionally, open stubs are utilized to enhance the stopband responses.

Plasma Generator with Dielectric Rim and FSS Electrode for Enhanced RCS Reduction Effect.

In this study, a method was experimentally verified for further reducing the radar cross-section (RCS) of a two-dimensional planar target by using a dielectric rim in a dielectric barrier discharge (DBD) plasma generator using a frequency selective surface (FSS) as an electrode. By designing the frequency selective surface such that the passbands of the radar signal match, it is possible to minimize the effect of the conductor electrode, in order to maximize the RCS reduction effect due to the plasma. By designing the FSS to be independent of the polarization, the effect of RCS reduction can be insensitive to the polarization of the incoming wave.

Compensation for Lateral Misalignment in Litz Wire Based on Multilayer Coil Technology.

This study applies a multilayer coil technology that can compensate for a decrease in transfer efficiency due to a lateral misalignment in a practical 100 kHz-band wireless power transfer system and validates its effect on the efficiency of compensation. The effectiveness is investigated using coils fabricated with Litz wires. Three-turn rectangular assistant coils 22.

Interdigital Capacitor-Based Passive LC Resonant Sensor for Improved Moisture Sensing.

Herein, a passive low-profile moisture sensor design based on radio frequency identification (RFID) technology is proposed. The sensor consists of an LC resonant loop, and the sensing mechanism is based on the fringing electric field generated by the capacitor in the circuit. A standard planar inductor and a two-layer interdigital capacitor (IDC) with a significantly higher fringing capacitance compared to that of a conventional parallel plate capacitor (PPC) are used, resulting in improved frequency offset and sensitivity of the sensor.

Wideband performance analysis of ground-plane cloak designed with polarization-independent randomly patterned metamaterial.

A ground-plane cloak is designed based on the quasi-conformal mapping method to hide a perfectly conducting object. It is fabricated with a metamaterial, a mixture of a dielectric and air. Using the dielectric mixing formula, the required volume fraction is calculated for a designed refractive index of the cloak.

Design method for broadband free-space electromagnetic cloak based on isotropic material for size reduction and enhanced invisibility.

A design method is proposed that not only improves the invisibility of but also minimizes the size of a two-dimensional (2D) free-space electromagnetic cloak based on the quasi-conformal mapping (QCM) technique. The refractive index profile of the cloak based on the QCM is optimally scaled to minimize performance deterioration due to the imperfect isotropy of the cloak medium. Moreover, the method can be applied to compensate for the performance degradation due to size reduction.

Printed UHF RFID antennas with high efficiencies using nano-particle silver ink.

One of the most popular targets of conductive ink technology is to print RFID tag antennas. However, the printed RFID antennas, manufactured by conductive silver ink which is generally based on microsized silver particles, have lower conductivity and consequently lower radiation efficiency than those by conventional copper etching method. This work demonstrates nano-particle conductive silver ink that is capable of printing UHF RFID antennas with improved radiation efficiency.