Jong K. Park

Scattering analysis of a coaxial line terminated by a gap

TEM-wave scattering on a coaxial line terminated by a gap is theoretically investigated. The Fourier transform and the mode matching are used to obtain a rapidly convergent series solution. Our solution is compared with Marcuvitz result based on the small-aperture method. Computations are performed to illustrate the phase behavior of reflection versus a gap variation.

A novel UWB antenna using PI-shaped matching stub for UWB applications

In this paper, we have proposed a compact UWB antenna with PI-shaped (pi-shaped) matching stub for UWB applications. The antenna has a modified trapezoidal radiating patch, a PI-shaped matching stub, CPW feeding, and two steps for impedance matching. To evaluate the dispersion performance of the designed UWB antenna, the path loss (|S21|) and the group delay are simulated and measured. Details of the proposed antenna design and the simulated and measured results are presented and discussed.

The Design of UWB Bandpass Filter-Combined Ultra-Wide Band Antenna

We have proposed a compact filter-combined ultra-wide band antenna for the use of DS-UWB low band or MB-OFDM lower three bands (3.1-5.2 GHz). The designed antenna has a microstrip-fed trapezoidal radiating patch, UWB band pass filter using the dumbbell-shaped DGS (defected ground structure) and IDC (interdigital capacitor), two steps for impedance matching, and microstrip feeding. Three kinds of prototypes (trapezoidal UWB antenna, UWB band pass filter, and the compact filter-combined ultra wideband antenna) are fabricated and measured. The designed antenna has the figure-of-eight radiation pattern, wide bandwidth, and negligible dispersion over the operating frequency band. Details of the proposed antenna design and the simulated and measured results are presented and discussed.

Transverse electric scattering from a gap on a circular waveguide

Electromagnetic transverse electric wave scattering from a circumferential gap on a conducting circular waveguide is theoretically investigated. The Fourier transform/series technique is used to constitute a set of simultaneous equations for the discrete modal coefficients. Residue calculus is applied to obtain a fast-convergent series solution that is amenable to the numerical computations. Extensive calculations are performed to examine the effects of a gap on the radiation and scattering.

Scattering from multiple grooves in the inner conductor of a coaxial line

A problem of electromagnetic-wave scattering from multiple grooves in the inner conductor of a coaxial line is theoretically solved. Simultaneous equations for the discrete modal coefficients are formulated by utilizing the Fourier transform. The reflection and transmission coefficients are obtained in numerically efficient fast-convergent series. Numerical computations are performed to show the frequency characteristics of the reflection and transmission coefficients in terms of the groove geometry.

Triple-band antenna with slots for PCS/WLAN/UWB applications

In this paper, we have proposed a triple-band antenna with L and T-shaped stubs for PCS/WLAN/UWB applications. The proposed antenna consists of two symmetrical strips, multi-steps, and L and T-shaped stubs. Two techniques are used to produce the two resonances at each frequency bands, the low dispersion, and good impedance matching. The proposed antenna has an omni-directional radiation pattern, compact size, low dispersion, and low cost.