• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.58 no.4
• /
• pp.465-468
• /
• 2009

The dispersion relation and the characteristic of propagation are measured. The measurements of the dispersion relation are observed by a plunger method employed in slow plasma density by pumping microwaves on the axis are observed in plasma loaded slow wave structure. In case of small incident microwave powers the well known plasma density cavity are observed. At the axial positions of minimal radius in the waveguides, the maxima og the electron density, the plasma potential and the RF electric field are observed in cases of high-power microwaves.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.58 no.4
• /
• pp.585-587
• /
• 2009

A large diameter slot waveguide made backward wave oscillator is investigated experimentally. The parameters of slow wave structure are chosen so that the oscillation frequency is about 20 GHz. Plasma is produced by the beam and it has favorable effects on beam propagation and Cherncov oscillation. The output power strongly enhanced when the guiding magnetic field approaches to the fundamental electron cyclotron resonance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.10 no.5
• /
• pp.694-700
• /
• 1999

In this paper, we studied the design of power divider using the slow-wave effect of Photonic Bandgap structure, which is etched on the ground plane. The proposed PBG structure can provides the changing of the characteristic impedance of the transmission line and the group delay velocity characteristic. Therefore we can make wider width than the width of conventional transmission line and decrease the length of transmission line. We presented the application for power divider using the characteristic impedance and electrical length extracted from scattering parameter. As adding proposed defect units, the effect of defect is studied. The experimental results show good agreements with the simulated results.

• Proceedings of the KIEE Conference
• /
• 2006.07c
• /
• pp.1554-1555
• /
• 2006

We have studied the backward wave oscillator, a power pulsed generator oscillator at 20 GHz has higher frequency then current one. An absolute instability linear analysis was used for the purpose of designing the slow wave structure. A large diameter of the slow wave structure was adopted to prevent the breakdown brought about by the increase of power density.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.12
• /
• pp.1059-1068
• /
• 2016

This paper proposes slow wave structure(SWS) utilized to increase antenna gain of printed dipole antenna(PDA) and to suppress sidelobe level simultaneously, and makes sure of electrical characteristics of the antenna according to parameter variations of components of the slow wave structure. The printed slow wave structure which is composed of a dielectric substrate and a metal rods array is located on excited direction of the PDA, affecting the radiation pattern and its intensity. Parasitic elements of the metal rods are arrayed in narrow consistent gap and have a tendency to gradually decrease in length. In this paper, array interval, element length, and taper angle are selected as the parameter of the parasitic element that effects radiation characteristics. Magnitude and phase distribution of the electrical field are observed and analyzed for each parameter variations. On the basis of these results, while the radiation pattern is analyzed, array methods of parasitic elements of the SWS for high gain characteristics are provided. The proposed antenna is designed to be operated at the Wifi band(5.15~5.85 GHz), and parameters of the parasitic element are optimized to maximize antenna gain and suppress sidelobe. Simulated and measured results of the fabricated antenna show that it has wide bandwidth, high efficiency, high gain, and low sidelobe level.

• Journal of Advanced Navigation Technology
• /
• v.15 no.5
• /
• pp.774-780
• /
• 2011

This paper presents a Bagley polygon and Gysel divider using open-stub loaded transmission line. The structure of slow-wave characteristic consists of small transmission line and shunt capacitive open stub that have reduced characteristic impedance and phase velocity, so we can implement the small circuit size. To validate the slow-wave characteristics, we are implemented the slow-wave characteristic of Bagley polygon and Gysel divider at center frequency 2.1 GHz. Its characteristics are same, but the circuit size is reduced above 15 % respectively.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.22 no.4
• /
• pp.66-71
• /
• 1985

A MOSFET with multigates arrayed in periodic structure is studied as a transit time device for microwave amplification. The interactions between the periodic metal gates and the slow wave on the surface of the semiconductor can be observed in the vicinity of synchronism. The stability and the reciprocity of the active quadrupole are shown depending on the frequency and velocity of the carriers.

• Journal of Advanced Marine Engineering and Technology
• /
• v.34 no.2
• /
• pp.325-331
• /
• 2010

In this study, highly miniaturized short-wavelength meander line employing eriodically patterned ground structure (PPGS) was developed for application to miniaturized on-chip passive component on GaAs MMIC (monolithic microwave integrated circuit). The meander line employing PPGS showed shorter wavelength and slow-wave characteristic compared with conventional meander line. The wavelength of the meander line employing PPGS structure was 17 % of the conventional meander line on GaAs MMIC. Due to its slow-wave structure, the meander line employing PPGS exhibited large propagation constant than conventional meander line, which resulted in larger phase shift and shunt inductance value. Above results indicate that the meander line employing PPGS is a promising candidate for application to a development of miniaturized on-chip RF components as well as inductor with a high inductance value on GaAs MMIC.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.11 no.5
• /
• pp.307-314
• /
• 1986

Propagation constants for TMon and TEon modes in a circular waveguide with a ring type dielectri are computed using the numerical analysis when the width of dielectric is varied regularly. This structure can be applied to the supporter to make improve the Q-factor of dielectric resonators, and the results of numerical calculation can be used to design the slow wave structures. Also, the numerical analysis in this paper can be used to determine the resonant frequencies in dielectric resonators.

• Journal of Korean Port Research
• /
• v.8 no.2
• /
• pp.67-77
• /
• 1994

A time-domain numerical model is developed to examine the performance of a wave energy focusing structure in combined waves and a current. With the current assumed to be slow and the structure fully submerged, the wave-current interaction problem is reduced to a wave scattering problem in a uniform current. The diffraction of incident waves around a narrow berm is considered. The shape of the berm is defined by a parabola, imitating that of an optical reflector. The energy focus is achieved by reflecting the incident waves through a predetermined focal point. Through the numerical simulations, the numerical model is shown to be effective in modeling the wave-current interaction problem, and the current speed and direction are shown to affect significantly the location, amplitude and sharpness of the focus.