Min-Gyo Jeong

A Continuous Power-Controlled Microwave Belt Drier Improving Heating Uniformity

Due to the nonuniform energy distribution in a microwave (MW) cavity, MW-based heating applications remain a substantial barrier. A continuous power-controlled MW conveyor-belt drier using multiple 2.45-GHz MW sources improves heating uniformity. By controlling the input power of MW sources sequentially, the electric field and temperature variations, hot and cold spots in the MW cavity, have been significantly reduced. Experimental results show that the MW heating using the proposed continuous power-controlled method can achieve an improved heating uniformity of approximately 34% compared with a simultaneous multiple input method (conventional mode).

INTERFERENCE ANALYSIS AND EXPERIMENTAL RESULTS OF PASSIVE UHF RFID SYSTEMS IN SUB-1 GHZ WIRELESS COMMUNICATIONS SYSTEMS

As ultra high frequency (UHF) radio frequency identification (RFID) technology, a smart recognition technology, has been gradually spreading to various applications, and several sub-1GHz wireless technologies are being standardized and developed. As such technologies operate at a specific frequency band (902–928 MHz industrial, scientific, and medical bands), the impact of RF interference due to performance degradation of UHF RFID technology on the interference signal is emerging as a new obstacle. In this paper, we investigate the interference analysis and experimental results of passive UHF RFID systems in sub-1GHz wireless communications systems. By considering interference signal frequency and power, interference deployment, antenna polarization, RF system-level analysis and experimental verification are conducted to evaluate the impact of performance degradation in the UHF RFID system on the interference signal.

A Printed Fan-Shaped Meandered Dipole Antenna With Mutual-Coupled Dual Resonance

This letter presents a printed fan-shaped meandered dipole antenna with mutual-coupled dual resonance for enhancing impedance bandwidth in a compact antenna size. The proposed antenna consists of a printed dipole antenna mutually coupled to an antenna parasitic element of a different size for dual resonance and microstrip feeding. By applying a fan-shaped meander-line structure, the proposed antenna occupies a low-profile miniaturized electrical size of 0.21

DRYING APPARATUS AND CONTROL METHOD THEREFOR

\lambda _0\times 0.21\lambda _0\times 0.08\lambda _0

Electric-field-coupled contactless ID sensor for cm-level high-precision positioning item-level tagging systems

at 920 MHz. The proposed antenna, which was implemented and fabricated on an FR-4 substrate, achieved a wide 10 dB impedance bandwidth of approximately 12% and a peak gain of 3.2 dBi. Depending on the antenna length at the two resonant frequencies, the impedance bandwidth in the proposed antenna can be controlled.