Hyeong-Seok Jang

Design of Low-Cost Chipless System Using Printable Chipless Tag With Electromagnetic Code

In this letter, a printable chipless tag with electromagnetic code using split ring resonators is proposed. A 4 b chipless tag that can be applied to paper/plastic-based items such as ID cards, tickets, banknotes and security documents is designed. The chipless tag generates distinct electromagnetic characteristics by various combinations of a split ring resonator. Furthermore, a reader system is proposed to digitize electromagnetic characteristics and convert chipless tag to electromagnetic code.

Close Proximity Effects of Metallic Environments on the Antiparallel Resonant Coil for Near-Field Powering

This study verifies close proximity effects of metallic environments on the antiparallel resonant coil for near-field powering based on the theoretical analysis and experimental measurements. Compared to the conventional coil with a forward loop, frequency shifting of the antiparallel resonant coil which consists of forward and reverse loops with opposite-direction currents is unchanged regardless of the proximity of metallic plates. Furthermore, highly efficient near-field powering for metallic objects can be achieved with the antiparallel resonant coil because of the added magnetic field caused by the image current of the metallic plates.

High-speed real-time hand effect tuning algorithm in hand-held terminal

In this paper, impedance tuning algorithm is proposed. To improve antenna radiation performance, antennas have high radiation efficiency and mismatched efficiency. The mismatched efficiency can be improved by the impedance matching circuit and matching algorithm. The proposed algorithm uses only standing wave ratio (SWR) information. The proposed algorithm is high-speed predicting antenna impedance algorithm. The algorithm running time is less than 25 ms.

Transmit/receive isolator for UHF RFID reader with wideband balanced directional coupler

A wideband balanced directional coupler for UHF RFID reader is proposed. The wideband balanced coupler has a high isolation feature insensitive to load variations. The transmit and receive isolation characteristic is achieved for UHF RFID band (860∼960 MHz). The proposed structure has an isolation of more than 45dB in the UHF RFID band according to the variations in matching.

ANALYSIS OF SCATTERING WITH MULTI-SLOTTED CYLINDER WITH THICKNESS: TM CASE

An exact series solution for radiation and scattering of the dielectric-loaded multi-slotted cylinder with thickness is formulated by using radial mode matching technique. The radiated and guided flelds are represented in terms of an inflnite series of radial modes. By applying the appropriate boundary conditions, the coe-cients of radiated and guided flelds are obtained. The behaviors of resonance features are characterized for variation in frequencies, source positions, slot thickness, and dielectric coating properties.

Scattering from cylindrical cavity-backed aperture with inner or outer longitudinal corrugations: TM case

The exact series solution to the scattering from cylindrical cavity-backed aperture with longitudinal corrugations is formulated by using a radial mode matching technique. The scattered and penetrated fields are represented as an infinite series of radial modes. By applying appropriate boundary conditions, the coefficients of the scattered and transmitted fields are obtained.

Performance Improvement Using Real-Time Detection of Time-Variant Load Impedance of the Receiver in Wireless Power Transfer System

In this paper, an analysis of the effect of time-variant reflected impedance and its detection method on wireless power transfer(WPT) systems are presented. The reflected resistance at WPT systems is very important parameter as it indicates how well matched antenna is and will exhibit high efficiency. Proposed detection method is based on transmitter current variation analysis with respect to frequency sweep. Using the proposed design method, a wireless power transfer system operating at the frequency of 125 kHz, is design and detect reflected impedance variation. The proposed design method provides good agreements between measured and simulated results. Therefore, The proposed detecting method provides a nonintrusive method to detect harmful object in WPT system.

Scattering From Two Concentric Thick Conducting Cylindrical Cavity-Backed Apertures

An exact series solution for scattering and transmitting of two concentric thick conducting cylindrical cavity-backed apertures is formulated by using radial mode matching technique. The scattered and penetrated fields are represented in terms of an infinite series of radial modes. By applying the appropriate boundary conditions, the coefficients of scattered and transmitted fields are obtained. The behavior of resonance features is characterized for variation of structures with another slotted cylinder inside.

Adaptive load impedance matching using 5-port reflectometer with computationally simple measurement

Five-port architectures are investigated as a reflectometer for adaptive load impedance matching. The proposed reflectometer requires computationally simple control loop. Moreover, the adaptive load impedance matching system in RFID UHF band are proposed. Using simulation and measurement studies, it is shown that the five-port architecture can be used as a low-cost, simple and high-performance reflectometer in adaptive load matching systems.

Transmission and shielding from a magnetic line current placed inside or outside of the multi-slotted circular cylinder

An exact series solution to the radiation and scattering of the dielectric-coated multi-slotted cylinder with thickness is formulated by a radial mode matching technique in the case of magnetic line source excitation. The transmitted and guided fields are represented in terms of the infinite series of radial modes. By applying appropriate boundary conditions, the coefficients of transmitted and guided fields are obtained. The behaviors of resonance features are characterized for variations in frequencies, source positions, slot thickness, and dielectric coating properties.