Byeong-Yong Park

A Magneto-Dielectric Handset Antenna for LTE/WWAN/GPS Applications

A compact multiband internal antenna covering LTE/GSM/GPS/DCS/PCS/UMTS bands (748-960 and 1575.42-2690 MHz) is presented for mobile terminals. The antenna combines a coupled-fed scheme and a magneto-dielectric material, which has low loss properties (magnetic loss tangent ) up to 3 GHz, thereby achieving not only reduced antenna size but also improved bandwidth. In addition, a T-shaped monopole feeding line generating parasitic capacitance is applied to the proposed antenna. It plays an important role to shift the resonances, especially in the low band. The overall size of the antenna is only 35 ×15 ×4 mm3, corresponding to 0.0875λ0 ×0.0375 λ0 ×0.01 λ0 ( λ0 is the wavelength at 750 MHz). The design process and the measured results of the proposed antenna are presented in detail.

A Planar Dipole for Multiband Antenna Systems With Self-Balanced Impedance

In this letter, we present a multiframe L-slot planar dipole loaded with a single microstripline for multiband antenna systems. The multiband is achieved by creating a multiframe L-slot on a host dipole and also by loading the host dipole antenna with a single microstripline to generate a couple of shunts and series of capacitive gaps with an inductive strip, eventually forming LC-like resonators. The antenna supports several wireless communication bands including: LTE bands at 1.7 ~ 1.8 and 2.3 ~ 2.6 GHz; WLAN bands at 2.4 ~ 2.5, 5.2, and 5.8 GHz; WiBro/WiMAX bands at 3 ~ 4 GHz. In addition, to validate the multiband behaviors, we also proposed a simple equivalent circuit for the designed antenna in which biconical transmission lines were adopted to model the host dipole sections. The simulation, fabrication, and measurement of the proposed antenna were implemented. As a result, its reflection coefficients |S11| were found to be better than -7 dB for most operating frequencies along with a sufficiently large bandwidth and good radiation patterns.

Design of a Planar Slotted Waveguide Array Antenna for X-band Radar Applications

A planar slotted waveguide array antenna has been designed at 9.37 GHz for X-band radar applications. The antenna consists of multiple branchline waveguides with broadwall radiating shunt slots and a main waveguide to feed the branch waveguides through a series of inclined coupling slots. The antenna feed point is located at the center of the main waveguide. Element weights in the array have been calculated bysampling a continuous circular Taylor aperture distribution at the 25 dB sidelobe level in both the E and Hplanes. A commercially available electromagnetic (EM) simulation tool has been used to characterize the individual isolated slot and that data hassubsequently been used to design the planar array. The array is finally analyzed in a CST Microwave studio and the measured and simulated results have been found to be in good agreement.

Calculation of Magnetization and Permeability Tensor of a Partially Magnetized Cylindrical Ferrite Resonator

A accurate method of calculating a magnetization and permeability tensor of ferrites is proposed in this paper. We introduce a cylindrical ferrite resonator that is located between parallel metal plates. We theoretically derive exact eigenvalue equations for the mode-splitting phenomenon of the HE111 mode. We also show that the mode-splitting behavior depends on a single magnetization value of the ferrite. The magnetization and permeability tensor components are computed from the measured resonant frequencies of the resonator. We present an analysis of cylindrical ferrite resonator and its experimental results.

Theory and Design of a Cylindrical Ferrite Resonator Antenna Using

A theoretical model of a cylindrical ferrite resonator antenna with a dc magnetic bias, applied in the direction parallel to the antenna height, is proposed. HE11δ mode splitting behavior caused by tensor nature of the permeability of a biased ferrite is investigated. The proposed model is validated through an experimental investigation of the HE11δ mode antenna. This communication utilizes a Li-ferrite suitable for the antenna applications. The presented theory is shown to correlate well with the measured results. It is also found that HE11δ mode splitting behavior of the antenna involves frequency and polarization, and bandwidth tuning performances. Therefore, the antenna is a good candidate for a multifunctional antenna.

{{\mathrm {HE}}}_{ {11\delta }}

The Doppler phenomena caused by a moving receiver or environmental scatters around a receiver were emulated in an AC (Anechoic Chamber) and a RC (Reverberation Chamber) using platform and mode stirring. In order to verify the emulated Doppler spread spectrum, the measured results in the AC and the RC were investigated by incorporating Jakess and 802.11 TGn Doppler models, respectively.

Mode Splitting Behavior

In this letter, we describe the Doppler phenomenon according to some antenna configurations in a reverberation chamber. The Doppler spread spectra with some rotational velocities of RX antenna using platform stirring are described. The Doppler effects of single and multiple antennas at 2.6GHz are characterized by polarization and spatial parameters.