• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.77-84
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• 2004

We design and implement the DSP module for automotive radar using FMCW. The designed parameters are based on 77GHz FMCW radar, and show the resolution of 0.4m and 0.67km/h in distance and velocity, respectively. For detecting multiple targets, we discuss the relationship between fb's and targets. In addition, we show that the detection of multiple targets is very simple when the range of $f_r$ is sufficiently larger than that of $f_b$. In the front of ADC, the 2nd order differentiator is applied for reducing the effects of path-loss so that the ADC bits are reduced to 8 bits. The designed block is simulated in Matlab and implemented with DSP and micro-processor.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.426-435
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• 2002

In this paper we present an indoor propagation model for indoor wireless LAN service in the ISM band. We primarily use a 3D ray tracing as well as a patch scattering model in order to take into account the indoor fixtures. Therefore input parameters such as indoor environment parameters and antenna's types, polarizations are considered. As the results, we present fading characteristics and rms delay spread from time delay spread. In order to investigate the accuracy of the presented model, comparisons of predictions with measurement and simulations are performed in indoor wireless LAN service environments. The results show that measurements and simulations are very similar. Therefore in this paper, the effect of presented indoor propagation model is confirmed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.803-808
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• 2003

Several dielectric pipes buried in the lossy half space are reconstructed from the scattered fields measured along the interface between the air and the lossy ground. Iterative inversion method by using the hybrid optimization algorithm combining the genetic and the Levenberg-Marquardt algorithm enables us to find the positions, the sizes, and the medium parameters such as the permittivities and the conductivities of the buried pipes as well as those of the background lossy half space even when the dielectric pipes are close together. Illposedness of the inversion caused by the errors in the measured scattered fields are regularized by filtering the evanescent modes of the scattered fields out.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.436-441
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• 2008

In this paper, we derived the Y-parameter of the recently reported Balun-BPF with a dual mode ring resonator by using the network analysis method. Using the derived Y-parameter we verified that the Balun-BPF structure satisfy the balun conditions. In order to design the Balun-BPF with arbitrary characteristics using the standard BPF design method with ease we derived the immittance slope parameters of the dual mode ring resonator with a load. The notch frequencies are also predicted. By designing with the proposed equations, simulating with a circuit simulator, fabricated and measured a Balun-BPF we confirmed the validation of the equations. The measured data shows bandwidth of 71 MHz and insertion loss of 0.92 dB at the center frequency of 2.46 GHz. It shows the phase imbalance of $174{\sim}181$ degree and the magnitude imbalance within 0.5 dB.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.66-69
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• 2016

In this paper, we suggests a Ka-band LNB considering next-generation UHD satellite TVRO. Since Ka-band has grater attenuation than Ku-band in atmosphere, we designed the low-noise down-converter to improve receiving sensitivity and to extend a dynamic range of receiver. It aims to compensate a quality of ultra high definition transmission signal for rainfall. The low-noise block diagram consists of a three-staged amplifier (LNA), band-pass filter for deleting image (BPF), mixer and IF when considering nonlinear characteristics in the receiver RF front end module. Also, we showed a LNB through optimization processes affecting dynamic range directly in receiver FEM. Asa resuly of experiment, the gain of low-noise down-converter show between 58.5dB and 60.7dB, the noise figure has a high characteristic as 1.38dB. Finally, the phase noise of local oscillator is -63.10dBc at 100MHz offset frequency.

• Journal of the Korean earth science society
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• v.36 no.4
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• pp.351-359
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• 2015

This study is to analyze the sensitivity for the parameters (a and b values, $M_{max}$, attenuation formula, and seismo-tectonic model) which are essential for the seismic hazard map. The values of each parameter were suggested by 10 members of the expert group. The results show that PGA increases as a value and $M_{max}$ become larger and as b value smaller. Big impact on the seismic hazard is observed for attenuation formula, a and b values although there is little impact on $M_{max}$ and seismo-tectonic model. These parameters with big impact require careful consideration for obtaining adequate values that well reflects the seismic characteristics of the Korean peninsula.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2444-2450
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• 2011

In this paper, we propose the low fractional spur phase-locked loop(PLL) with multiple phase-frequency detector(PFD). The fractional spurs are suppressed by using a new PFD. The new PFD architecture with two different edge detection methods is used to suppress the fractional spur by limiting a maximum width of the output signals of PFD. The proposed PLL was simulated by HSPICE using a 0.35m CMOS parameters. The simulation results show that the proposed PLL is able to suppress fractional spurs with fast locking.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.601-610
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• 2004

In this paper, the performance of an adaptive array antenna using Constant Modulus Algorithm (CMA) based on the signal structure for the IMT-2000 3GPP specification reverse link of an asynchronous direct sequence code division multiple access (DS-CDMA) system are evaluated. In addition, the performance is compared with the array antenna using Least Mean Square (LMS) based on the training signal. The simulation parameters such as the number of multipath, mu10pa1h intensity profiles between path, spreading gain and multiuser etc., are considered in the Monte Carlo simulation. Simulation results demonstrate an adaptive array antenna using CMA may give more capacity gain than the amy antenna using LMS in the case of multipath fading channel.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1255-1260
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• 2009

Microstrip interdigital filter is designed with the width and length of a resonator, the gap distance between resonators and the location of a tap. When designing filters, it is a benefit to design with few design parameters comparing to many design parameters. In this paper we design and implement two microstrip interdigital filters operating in the UWB(Ultra Wide-Band) frequency band, one using a fixed width of a resonator and the other using a different width of resonators. The test results of the implemented filters show that the low-band high filter with a fixed width has the insertion loss of 1.49dB, -10dB band width of 720MHz, -35.7dBattenuation at 4.8GHzand below -13dB of S11. The filter with a different width of resonators has the insertion loss of 1.6dB, -10dBbandwidth of 1.63GHz and below-8dBof S11.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6A
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• pp.499-509
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• 2005

The capacity of Satellite DMB(Digital Multimedia Broadcasting) system is limited mainly by the interference. So, to achieve the expected performance of Satellite DMB system and to minimize the interference from other Satellite DMB system, ACI(Adjacent Channel Interference) should be considered carefully. Satellite DMB system uses the Gap-filler for effective transmission in terrestrial environment, and the Gap-filler can use direct amplification or frequency conversion to satisfy the specific requirements. Therefore, amplified signal causes several effects on interference between System A(Eureka 147 DAB) and System E(ISDB : Integrated services Digital Broadcasting). In this paper, by using the outcome of system-level simulation considering the results of link-level simulation, we analyze the interferences between System A and System E under practical situation based on the exact parameters of ITU-R BO. 1130-4. We also propose the appropriate level of guard band and Cell Radius to optimize system capacity by adapting the spectrum mask given in the spec. and utilizing the interference analysis between System A and System E.