• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.373-379
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• 2005

Papers on improvement of electromagnetic field uniformity in a reverberation chamber with 1D Quadratic Residue Diffuser of Schroeder method has been published several times. In this paper, to obtain improved electromagnetic field characteristics and field uniformity in a reverberation chamber, cubical residue diffuser sets of Schroeder type are designed for a chamber in $2.3\;\cal{GHz}\~3\;\cal{GHz}$. The FDTD(Finite-Difference Time-Domain) technique is used to analyze the field characteristics in a chamber. Cubical residue algorithm and 2D arrangement show more randomness than the previous study results. The characteristics of tolerance, polarity, deviations, as well as power efficency, are improved with cubical residue diffuser sets in a chamber.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.1 s.104
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• pp.74-80
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• 2006

This paper presents the characteristics of electromagnetic field uniformity in a reverberation chamber that can be used alternatively for the analysis, test and evaluation of electromagnetic interference and immunity. The dual-band diffuser, which can be used at two different frequency bands in a reverberation chamber, is applied, and it is made of two different single-band Schroeder's Quadratic Residue Diffusers. The FDTD method is used to analyze the field characteristics. Compared with single-band diffuser, the dual-band diffuser shows the improvement in not only expansion of test frequency band but also in characteristics of the field uniformity, polarity, power efficiency, and tolerance. Therefore, the reverberation chamber with the dual-band diffuser is a better facility, for the analysis and measurement of electromagnetic interference and immunity, than the reverberation chamber with a single-band diffuser.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.837-843
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• 2001

Conventional reverberation chamber has a rectangular structure including mode stirrers or mode-turned stirrers to obtain the field uniformity inside the chamber. This paper explained the way to improve the field uniformity in an asymmetric structure instead of conventional rectangular structure with right-angled planes. Two types of asymmetric structure were considered. One was an asymmetric reverberation chamber using Quadratic Residue Diffuser and the other was an asymmetric chamber with oblique enclosure including fixed Randomly Made Diffusers. The FDTD simulation method was used to analyze the field homogeneous characteristics of these asymmetric reverberation chambers.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1222-1228
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• 2005

Analysis on the field uniformity inside of a reverberation chamber was done at 2.45 GHz which is an operating frequency of MWO(Microwave Oven). The Schroeder's Quadratic Residue Diffuser was designed for the chamber, and 3 different types of diffusers have been investigated using the finite-difference time-domain(FDTD) method for the field characteristics of each type. Type 2 and 3 diffusers were filled with dielectric material, and the size of these could be designed smaller than Type 1, without degradation of field characteristic. Type 3 diffuser shows better results among the three types of diffusers in view of increased test region and better field uniformity.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.2
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• pp.227-233
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• 2001

Electromagnetic field characteristics of Reverberation chamber, which could be applicable for an alternative test facility of electromagnetic interference and radiated electromagnetic susceptibility have been investigated. To obtain the required field uniformity of reverberation chamber, Schroeder method Quadratic Residue Diffuser was designed to be applied to chamber. In this paper, 3 different types of diffusers depending on diffuser's periodic direction have been used to investigate field characteristics of each type by using FDTD numerical method. The results show all 3 types of reverberation chambers have below $\pm$3 dB tolerance of field uniformity characteristics, and the symmetrical, type 3, structure show better results among them.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.8
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• pp.121-127
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• 2008

This paper presents an electric field distribution in a reverberation chamber using cylindrical diffuser. The characteristics of electric field distributions are compared with QRD(Quadratic Residue Diffuser) and cylindrical diffuser for $1{\sim}3$ GHz frequency band. The FDTD(Finite-Difference Time-Domain) method is used to analyze the field characteristics, and the field uniformity. At 2 GHz, the standard deviation and the tolerance of test volume in the reverberation chamber are improved by 0.11 dB, 0.43 dB for the case of cylindrical diffuser. The field strength is increased by 43.2 dBmV/m vs QRD's of 36.6 dBmV/m. Comparing with QRD's, the characteristic of polarization is also improved. These results show that reverberation chamber using cylindrical diffuser can be used alternative facility for measurement of electromagnetic interference and immunity.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.577-583
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• 2007

The field uniformity inside the reverberation chamber has been improved using sets of quadratic residue diffuser (QRD). The electromagnetic field inside the reverberation chamber with the dimension of $100{\times}80{\times}80cm$ has been analyzed by the finite-difference time-domain(FDTD) method. The calculated fields in a $40{\times}30{\times}30cm$ test volume have been sampled to obtain a standard deviation and field uniformity. Results show that the standard deviation of the calculated field and uniformity have been improved by varying angles and orientation of the inclined surfaces of the QRDs installed inside the reverberation chamber.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.211-214
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• 2000

본 논문은 전자파 장해 및 복사내성 측정의 대용 시험시설로 활용될 수 있는 전자파 잔향실의 전자기장 특성에 관하여 연구하였다. 전자파 잔향실 내부 균일성을 확보하기 위하여, 음향효과의 극대화를 위해 인간의 가청 주파수대인 16-20,000Hz 범위, 음속(340 m/sec)에 적용하여 활용되고 있는 Shroeder Quadratic Residue Diffuser를 무선 주파수 대역 30 KHz -3 THz인 범위로 확장, 3가지 형태의 Diffuser를 설계하여 잔향실 내부에 적용하였다. FDTD(Finite-Difference Time-Domain) 수치해석 방식을 이용하여 잔향실 내부의 필드 특성을 조사한 결과 Diffuser를 부착한 3 가지 형태 모두 치대 tolerance $\pm$3dB 이내의 필드 균일도를 나타내었으며, Type 3, 대칭형 구조의 Diffuser 형태가 효율이 가장 우수하다는 결과를 나타내었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.4 s.119
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• pp.372-378
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• 2007

This paper presents an improvement of field uniformity in a reverberation chamber with QRDs(Quadratic Residue Diffuser) and also shows the optimal dimension of the QRDs. The QRD is designed for $1{\sim}3\;GHz$ frequency band and the FDTD(finite-Difference Time-Domain) method is used to analyze the field characteristics. At 2 GHz, the standard deviation of test volume in the reverberation chamber is the smallest when the QRD has $30{\sim}60\;%$ coverage of one side of the reverberation chamber and the field uniformity is worsened when the coverage of the QRD is either below 20 % or above 70 % of the area of the side wall. Particularly, the standard deviation of test volume in the reverberation chamber with 30 % coverage of QRD is improved by 1.53 dB compared to that of the reference chamber with no QRDs.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.83-86
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• 2021

In this paper, electric fields in electromagnetic reverberation chambers, which are used as a substitute facility for EM-free anechoic chambers, are analyzed. This paper focused on the 4-5 GHz band, which is expected to adversely affect equipment. To analyze the field uniformity inside the electromagnetic reverberation chamber, electric field strengths are sampled and finite-difference time-domain method was used for numerical analysis. Moreover, Quadratic residue diffuser was used to improve the characteristics of the electromagnetic reverberation chamber and the uniformity of the internal field strength. Standard deviation, tolerance characteristics, and partiality characteristics were compared while varying the aiming point of transmission antenna.