Sinhyung Jeon

Controlling Resonances for a Multi-Wideband Antenna by Inserting Reactive Components

A novel method is proposed to control the resonance frequencies of an antenna for multi-wideband operation. The parallel addition of reactive components to an antenna shifts the resonance frequencies without increasing the size of the antenna. These resonance frequency shifts can be analyzed by observing the voltage difference via an approach based on an open-circuit transmission line. The designed antenna has 180 MHz (940-1120 MHz) and 630 MHz (1970-2600 MHz) bandwidths under VSWR=2.5:1 with a high radiation efficiency at dual-band. The lower and the higher bands of the antenna provide coverage for Global System for Mobile communications 900 (GSM900), Universal Mobile Telecommunications System 2100 (UMTS2100), Wireless Broadband (WiBro) and Bluetooth.

Design of gap-fed antenna adjacent to ground of a mobile handset

In this paper, an antenna for mobile handsets is considered as a lossy transmission line to study the effect of distance between an antennas and ground. From this model, it is shown that a characteristic impedance of an antenna affects the input impedance. This paper proposes a gap-fed monopole antenna to reduce the proximity effect of a ground plane.

Ferrite sheet loaded PIFA for critical couping

A method which can achieve the critical coupling of PIFA is proposed. It is accomplished by only attaching the ferrite sheet without changing the structure of the antenna. It is modeled by equivalent circuit based on transmission line modeling and the critical coupling can be confirmed by Smith chart of the antenna. The proposed antenna is verified by 3D EM simulator. The ferrite sheet loaded PIFA can easily attain to critical coupling and it has sufficient bandwidth, 880-1040 MHz (VSWR<2).