Sangbong Jeon

Simple Method to Generate Dominant E- and H-Fields Inside a Four-Port TEM Cell

We propose a simple method to generate dominant E (DE)- or dominant H (DH)-modes, which builds near-field like environments in a four-port transverse electromagnetic (TEM) cell. Each DE or DH mode is intended to present very high or very low impedance values, which remain stable over a wide frequency region of interest. To achieve this, we apply signals, in- or out-of-phase, into ports that are connected to separate septum terminated by matched loads, which guarantees good impedance matching behavior. In addition, our cell also yields enhanced field uniformity in an extended test volume surrounded by the septa. All experimental data show excellent agreement with theoretical prediction, which proves the validity and usefulness of our approach.

Study of a four-port TEM cell with the statistical approach for the calibration of EM field probe

The transverse electromagnetic (TEM) cells are widely used for field probe calibrations. We propose the verification of TEM mode with statistical method using a four-port TEM cell. The verification results are compared with Normal, Rayleigh, Gamma distribution. As a result, the 75 % quantile of the Rayleigh distribution is excellent agreement with the true quantiles for a number of calibration points.

Reactive near-field to near-/far-field transformation in semi-anechoic chamber

In this paper, the technique of the reactive near-field to near-/far-field transformation has been proposed. The different thing compared with the previous work is that the environment of the semi-anechoic chamber with the ground plane was assumed during the transformation. The sources of electronic device are reconstructed from the detected reactive near-field. And then, the composite array source using the image theory is built, and then the transformation from the composite source to the near-/far-field are performed. For the verification, the simulated results have been utilized, and their results show small errors. Therefore, the proposed technique in this paper could be applied to predict the radiated field at 3 m or 10 m without the expensive large semi-anechoic chamber.

Study of the throughput of WLAN according to channeling and density of AP

This study is dedicated to investigate WLAN throughput based on 802.11 data communication standard which employs 2.4GHz band, depending on its AP channels and density. In a space with high density of WLANs, throughput can be decreased due to radio wave interferences. In light of this fact, an experiment scenario has been created consisting of multiple WLANs where throughput can be measured with different combination of channels, consequently making it possible to determine more effective combination of channels. In parallel, throughput has been recorded with varying the number of APs installed within the experiment site to Fig. out the relationship between the number of APs and the throughput. According to the result of the measurement, channel 1, 5, 9, and 13 are suggested as more effective combination of channels, and declining throughput is shown as AP density increases.

Experiment of the Throughput of WLAN according to Channelling and Density of AP

Abstract This paper is about the experiment which is throughput of WLANs based on 802.11 due to interference each other. Recently, WLAN has been increased due to generalization of smart-phone and potable notebook. Therefore, the decrease of throughput because of interference between WLANs is expected. In regard of this, the throughput of WLANs acc-ording to channelling is measured in order to figure out efficient channelling and the throughput of WLANs according to the number of AP was measured in order to get relation between number of AP and throughput. Then, more efficint channelling of 1, 5, 9, 13 is suggested and the throughput of WLAN is decreased as increasing of number of AP. Key words : Radio Interference, WLAN, Channelling, Throughput Ⅰ . 서 론 전세계적으로유비쿼터스시대를넘어스마트시대구현을위한다양한무선서비스가개발되어상용화되고있으며, 이러한서비스의실현을위해고속의정보전송을위한광대역특성을갖는최첨단IT 및멀티미디어기기들의사용이증가하고있는추세이다 [1] . 이러한추세는새로운주파수에대한수요를증가시켜한정된주파수자원의고갈문제에직면하게되고, 이문제를해결하기위해주파수효율성을극대화하는동시에상호간에간섭을최소화하는노력이절실히요구되고있다. 최근에는, 무선랜 ⓒ Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved

A consideration on the electrodeless fluorescent lamp and its radio interference characteristics

The electrodeless fluorescent lamp (or magnetic induction lamp) is relatively new luminaire and has been known as the high energy saving lamp which has long life and environment-friendly. But induction lamps (hereafter, ‘electrodeless fluorescent lamp’ can be simplified as ‘magnetic induction lamp’ or ‘induction lamp’ for convenience) have some risks to cause harmful radio interference unavoidably due to its own inductive characteristics. In this paper we measured the radio disturbance characteristics of the induction lamps with two kinds of operating frequencies, and compared the values with the limits of relevant standards. Finally we have estimated the interference protection distance between the induction lamps and some services around their operating frequencies, and considered the desirable future scopes and limits of the induction lamp applications.