• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.12
• /
• pp.1399-1405
• /
• 2012

Transmission cross section characteristics as a measure of transmission efficiency has been analyzed numerically for the H-shaped and C-shaped small apertures in the infinite conducting plane when illuminated by a plane wave. It has been found that C-shaped aperture has the larger transmission cross section than that of H-shaped aperture under the condition of the same perforated aperture area. Main attention has been focused on studying the mutual coupling effect between two C-shaped apertures on the transmission cross section characteristic. Parallel configuration which is composed of two C-shaped apertures arranged along the x-axis and collinear configuration which is composed of two C-shaped arrayed along the y-axis have been investigated from the viewpoint of enhanced transmission cross section characteristics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.8
• /
• pp.781-787
• /
• 2004

In this paper, a novel dual and wide band aperture stacked patch antenna for Cellular/PCS/IMT-2000 base station is presented. It consists of single microstrip patch having notches along the radiating patch, two dielectric substrates and a form material. To achieve wide band characteristic, we utilize the coupling effect between the notched patch and the resonant aperture in the ground plane and by properly cutting notches on the patch, an aperture stacked patch antenna could be designed to yield dual frequency operation. By the proper choice of resonant aperture size and height of a foam material, dual and wide band characteristic could be realized the measured impedance bandwidth(1:1.5 VSWR) of designed antenna at lower band(860 MHz) reaches 77 MHz and covers the Cellular CDMA band(824∼894 MHz). The measured impedance bandwidth(1:1.5 VSMR) of the designed antenna at upper band(1,960 MHz) is about 550 MHz and covers both the PCS band(1,750∼l,870 MHz) and the for-2000 band(1,920∼2,170 MHz). Good broadside radiation with high gain(5.65∼7.4 dBi) characteristics have also been observed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.10 no.1
• /
• pp.142-149
• /
• 1999

In this paper, Aperture-coupled microstrip array antenna was designed and manufactured for satellite communication at Ka-Band. We analyzed a microstrip radiation element and designed power divider using $\lambda$g/4 transformer and T-junction power divider. A manufactured Aperture-coupled $2\times2$ microstrip array antenna has a resonant frequency of 20 GHz. The experimental results are as followings : resonant frequency of 19.62 GHz, VSWR 1.0692, return loss -29.61 dB, Bandwidth 1.76 GHz and -3 dB beamwidth $42^{\circ}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.3
• /
• pp.425-431
• /
• 2001

In this paper, on aperture-coupled microstrip cylindrical dielectric resonant antenna(DRA) consisting of dielectric material with permittivity ${\epsilon}_{r}$ = 36 is designed and fabricated fir wireless LAN. First of all, the feedline length, width, slot length and width of the feeding element were calculated using the theory of microstrip transmission line. Radiation element is designed using the theory of cylindrical dielectric cavity, Resonant frequency of the fabricated cylindrical DRA is 2.449 GHz and VSWR, return loss and bandwidth is 1.009, -47 dB and 70 MHz, respectively. Front-to-back radiation ratio is about 12 dB and 3 dB beamwidth of E-plane and H-plane is 110$^{\circ}$ and 90$^{\circ}$ , respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.12
• /
• pp.1198-1204
• /
• 2013

As a microwave near field probe for near field scanning optical microscope(NSOM) system, H-shaped(ridge type) small aperture is proposed and its performances from the viewpoints of the transmission efficiency(transmission cross section) and spatial confinement(beam spot size) are compared with those of the previous narrow rectangular aperture type. While the transmission efficiencies are comparable to each other for the two structures, the transmitted beam spot size for the proposed H-shaped aperture is much smaller than that for the previous rectangular aperture. This strong point of the H-shaped aperture is expected to significantly improve near-field optical applications such as optical data storage, nanolithography and nanomicroscopy. It is also observed that the transmission efficiency can be improved if the coupling aperture is implemented in the type of the transmission cavity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2000.05a
• /
• pp.101-104
• /
• 2000

In this paper. the electric field intensity has been theoretically evaluated by the method of moments in a cavity by a external source. The numerical results show a good agreement with the results of other papers. It is found that the electromagnetic penetration through aperture in the cavity shows peak values at some frequencies dependent largely on the structure of the cavity and aperture.

• Proceedings of the IEEK Conference
• /
• 2003.11c
• /
• pp.327-330
• /
• 2003

A novel compact circular polarization operation of the microstrip antenna with four-slits and T-slits is proposed. The mechanism for compact size antenna is investigated with the behavior of the currents on the radiating patch. The equivalent surface current path due to the slits is lengthened, reducing the resonant frequency at a fixed patch size. The proposed compact CP design can have an antenna size reduction of about 33 ∼ 45％ as compared to the conventional microstrip antenna. Details of the experimental and measured results are presented and analysed.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.10
• /
• pp.103-108
• /
• 2004

In this paper, a compact patch antenna with four T-slits fed by crossed aperture coupling is proposed for miniaturized Portable GPS handsets. The mechanism for compact size antenna is investigated with the behavior of the currents on the radiating patch. The equivalent surface current path due to the slits is lengthened, reducing the resonant frequency at a fixed patch size. The results of embedded T-slits for compact antenna size show that the resonant frequency is significantly lowered from 2.545GHz to 1.575GHz, corresponding to a 44.65% antenna size reduction compared to reference design. Experimental results show that good CP radiation patterns are obtained and impedance bandwidth (VSWR $\leq$ 2), 3dB axial ratio are about 21MHz, 19MHz at the center resonant frequency, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.1
• /
• pp.106-113
• /
• 2011

In this paper, the non-resonant SWG(Slotted Waveguide) antenna with double slots in narrow wall of rectangular waveguide is designed. Because energy radiated from each slot depends upon inclination angle of slot of the designed antenna, inclination angle of each slot is controlled to satisfy the amplitude distribution for required sidelobe level. Instead of the conventional extraction method of slot conductance, this amplitude distribution is made by the proposed method, which employs far-field radiation pattern calculated by Fourier transform of aperture field distribution on slot. The non-resonant double SWG antenna is designed by the proposed method and is manufactured. The antenna performances are measured and compared with the simulated results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.4
• /
• pp.507-514
• /
• 2012

This paper proposed the analysis method of the cavity resonance characteristics for a metallic enclosure with a PCB trace source. In order to calculation the electromagnetic fields inside the cavity, coupled integral equations for a current distribution on the PCB trace and an aperture electric field distribution on the boundary of the PCB dielectric are derived and solved by applying Galerkin's method of moments. The result show that the resonant characteristics of the metallic enclosure are fairly good agreement with the simulation(HFSS) and the measured results. The resonant frequencies of the metallic enclosure with the PCB trace are changed by the PCB trace location inside of the cavity. In order to check the validity of the theoretical analysis, the calculated return losses are compared with the measured results.