Design of Novel Wiggly Directional Coupler with the Fractal Coupled Sections for Improving Coupling

Hong, Ic-Pyo The Korea Institute of Information and Commucation 2008 Journal of information and communication convergen Vol.6 No.1

In this paper, the new type wiggly directional coupler which uses the fractal coupled shape in coupled sections is presented. A commercial software has been used to analyze this new structure and the simulation results are compared to those of the conventional wiggly directional coupler. To verify the simulation results, the new type wiggly directional coupler was fabricated with the center frequency of 15GHz. The measurement results shows that the coupling of new structure proposed in this paper is more than that of conventional wiggly coupler. The results in this paper also show that the fractal shape coupled lines in wiggling sections can improve the coupling characteristics in wiggly directional coupler.

Investigation of the Finite Planar Frequency Selective Surface with Defect Patterns

Hong, Ic-Pyo The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.4

In this paper, RCS characteristics on defect pattern of crossed dipole slot FSS having a finite size have been analyzed. To analyze RCS, we applied the electric field integral equation analysis which applies BiCGSTab algorithm with iterative method and uses RWG basis function. To verify the validity of this paper, RCS of PEC sphere has been compared to the theoretical results and FSSs with defect patterns are fabricated and measured. As defect patterns in FSS, missing one column, missing some elements, and discontinuity in surfaces are simulated and compared with the measurement results. Resonant frequency shifts in pass band and changes in bandwidth are observed. From the results, precisely predicting and designing frequency characteristics over defect patterns are essential when applying FSS structures such as FSS radomes.

Quasi-static Analysis on the Effect of the Finite Metal with the Anisotropic Grooved Dielectric in Microstrip Lines

Hong Ic-Pyo The Korean Microelectronics and Packaging Society 2005 마이크로전자 및 패키징학회지 Vol.12 No.1

In this paper, we presented the quasi-static characteristics of novel microstrip lines with anisotropic grooved dielectric in finite metal. A quasi-static mode-matching method has been used to analyze this new structure and the simulation results are validated through comparison with other available results. The results in this paper show that it is possible to control the propagation characteristics of microstrip lines with the use of anisotropic grooved dielectric in finite metal. Also anisotropic grooved dielectric in microstrip line can be newly added to the design parameters of high performance three dimensional monolithic microwave circuits and other microwave applications.

Evaluation of Common Building Wall in See-Through-Wall Application of Ultra-wideband Synthetic Aperture Radar

Ic-Pyo Hong,Nguyen Trung Kien 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.1

This paper presents the reproduced images of various objects from synthetic aperture radar (SAR) technique with ultrawideband (UWB) signals to evaluate the performance of common building walls in the see-through-wall capability regarding security applications, object along with human detection. The walls were designed from four materials, i.e., drywall, wood, insulation, and brick, which are used in real environments. The images of the objects behind the walls were performed using the commercial UWB radar with 2.2 GHz frequency bandwidth, 2 ns of pulse width, 10 MHz of internal repetition frequency, as well as an image reconstruction algorithm. From the measurement result, the insulated wall degraded the SAR image quality. Consequently, a material that enhance the UWB signal as Frequency Selective Surface should be considered to enable SAR for disaster applications.

Investigation of the Finite Planar Frequency Selective Surface with Defect Patterns

Ic-Pyo Hong 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.4

In this paper, RCS characteristics on defect pattern of crossed dipole slot FSS having a finite size have been analyzed. To analyze RCS, we applied the electric field integral equation analysis which applies BiCGSTab algorithm with iterative method and uses RWG basis function. To verify the validity of this paper, RCS of PEC sphere has been compared to the theoretical results and FSSs with defect patterns are fabricated and measured. As defect patterns in FSS, missing one column, missing some elements, and discontinuity in surfaces are simulated and compared with the measurement results. Resonant frequency shifts in pass band and changes in bandwidth are observed. From the results, precisely predicting and designing frequency characteristics over defect patterns are essential when applying FSS structures such as FSS radomes.

반파장 다이폴 안테나의 시간영역 과도응답을 이용한 전파경로손실 특성

홍익표(Ic-Pyo Hong) 한국정보기술학회 2013 한국정보기술학회논문지 Vol.11 No.5

In this paper, we analyzed the radio propagation path loss for the vertical half-wavelength electric dipole antenna over the perfect electric conductor(PEC) ground plane using the transient electromagnetic response in time domain. Electromagnetic response of dipole antenna was derived from the electromagnetic analysis in frequency domain and the electromagnetic response in frequency domain transformed into the transient response in time domain. Using the simulated results, we calculated the transient response in time domain for the height of transmitted dipole and the distance between transmitting and receiving antenna and obtained the path loss characteristic. The results of this paper can be applied to the propagation channel characteristics in time domain and surface radar applications.

Cagniard-de Hoop 방법을 이용한 시간영역 전파경로 손실 계산

홍익표(Ic-Pyo Hong) 한국정보기술학회 2013 한국정보기술학회논문지 Vol.11 No.4

In this paper, we derived and calculated the path loss of radio propagation with the use of the Cagniard-de Hoop method, which is one of time domain analysis method in electromagnetics. Cagniard-de Hoop method was proposed to analyze the time domain electromagnetic phenomena of the multilayer medium without dispersion. Transient responses in time domain between the base station and mobile are simulated with the assumption of perfect electric conductor for ground plane and vertical electric dipole antenna for base station. We also presented the radio propagation loss of free space with the ground for the prediction of channel fading characteristics. The proposed method can be used for the theoretical path loss prediction of wireless communication network design.

PSO를 이용한 주파수 선택 구조 기반 인공 자기 도체 설계

홍익표(Ic-Pyo Hong),이경원(Kyung-Won Lee),육종관(Jong-Gwan Yook),조창민(Chang-Min Cho),전흥재(Hueng-Jae Chun) 한국전자파학회 2010 한국전자파학회논문지 Vol.21 No.6

본 논문에서는 주파수 선택 구조를 기반으로 하는 인공 자기 도체 구조를 설계하기 위하여 최적화 알고리즘 중 하나인 particle swarm optimization(PSO) 기법을 이용하였다. 주파수 선택 구조로서 Jerusalem Cross를 갖는 인공 자기 도체의 등가 회로 모델에 PSO를 적용하여, 원하는 공진 주파수 대역을 갖는 최적의 설계값을 얻어낼 수 있음을 확인하였다. 우선 유도한 등가 회로 모델로부터 공진 주파수와 반사 계수 위상 특성을 구하여 상용 소프트웨어로 얻은 값과 일치하는 것을 확인하여 본 논문의 유효함을 확인하였으며, 이로부터 원하는 공진 주파수에 대해 최적화 과정을 통하여 설계 파라미터를 추출하였다. 본 논문에서 유도한 최적화 과정을 이용한 주파수 선택 구조 기반 인공 자기 도체 구조 설계 방법을 이용하여 여러 다른 종류의 주파수 선택 구조 형태를 갖는 인공 자기 도체 구조뿐만 아니라, 인공 자기 도체 구조를 이용한 소형 안테나 접지면 설계 등 마이크로파 회로 설계에 유용하게 사용할 수 있다. In this paper, particle swarm optimization(PSO) is applied for the design of frequency selective surface based artificial magnetic conductor. An equivalent circuit model for this artificial magnetic conductor(AMC) with Jerusalem Cross arrays was derived and then PSO was applied for obtaining the optimized geometrical parameters with desired resonant frequency. The resonant frequency and the reflection phase characteristics from the optimization were compared to the results from commercial software for verifying the validity of this paper. The procedure presented in this paper can be applied to design the AMC with different frequency selective surface and also can be used for the design of microwave circuits like the AMC ground planes.

스텔스 기능을 갖는 위장막의 RCS 특성 해석

홍익표(Ic-Pyo Hong) 한국정보기술학회 2015 한국정보기술학회논문지 Vol.13 No.4

In this paper, radar cross section(RCS) characteristics for camouflage net are analyzed. Camouflage net is one of solutions which is used for stealth applications in fixed earth weapon or non-stealth weapon system to conceal the tank or military truck. To calculate the attenuation and RCS characteristics of camouflage net, the thickness, relative permitivity and permeability of camouflage net are investigated as design parameters. We used the locally planar approach to calculate the electromagnetic field because the wavelength of the detecting radar is longer than the thickness of camouflage net. From the simulation results, we know that the increase in thickness, the small imaginary value of relative permitivity and permeability could provide the better performance of RCS reduction. Also we have a conclusion that the design parameters of camouflage net must be optimized to obtain the desired RCS performance.

스텔스 전투기 캐노피를 위한 투명 전자파 흡수구조 설계

홍익표,Hong, Ic-Pyo 한국군사과학기술학회 2015 한국군사과학기술학회지 Vol.18 No.4

In this paper, transparent circuit analog radar absorbing structure with angular stability for stealth aircraft canopy was proposed and designed. To obtain wideband electromagnetic absorption, optical transparency and smaller thickness, we proposed the novel FSS(Frequency Selective Surface) for X-band and implemented the resistive FSS and PEC(Perfect Electric Conductor) plane using ITO(Indium Thin Oxide) coating with optical transmissivity of 90 %. Reflection loss characteristics for different incident angles of both TE(Transverse Electric) and TM(Transverse Magnetic) polarizations are presented through simulations. We then fabricated the proposed structure to verify the simulation results. The comparisons between the simulation and measured results show good agreements. The results also show that the proposed radar absorbing structure can provide better frequency stability for different incidence angles and polarizations as well as optical transparency. We can apply this proposed structure to the canopy of stealth aircraft and other stealth applications for visible transparency.