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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Electromagnetic Engineering and Science
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Journal DOI :
The Korean Institute of Electromagnetic Engineering and Science
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Volume & Issues
Volume 11, Issue 8 - Dec 2000
Volume 11, Issue 7 - Oct 2000
Volume 11, Issue 6 - Sep 2000
Volume 11, Issue 5 - Aug 2000
Volume 11, Issue 4 - Jun 2000
Volume 11, Issue 3 - Apr 2000
Volume 11, Issue 2 - Feb 2000
Volume 11, Issue 1 - Jan 2000
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Fast and Efficient FDTD Analysis for Microstrip Structures
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1297~1304
The full wave method requires a great number of computer memory and lasting long CPU time for the calculation of the discontinuity problems in microstrip structures. While the computation only for the transverse field components at those structures causes the both of time and memory reduction. For the case of the calculating only transverse components for the most of microstrip structures such as low-pass filter, branch coupler and patch antenna the computer memory and running time can be reduced to about 50% and 33%, comparing to the full wave computation. Consequently, the proposed method than that of TEM-mode has an advantages of higher speed and less memory than that of conventional FDTD analysis.
Design of the CPW Band-Pass Filters Using the Finitely Backed Conductor
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1305~1312
This paper presents the design and implementation of the CPW end-coupled band-pass filter with the finitely backed conductor (FBC). To reduce the large insertion loss in CPW structure, the improvement in loss characteristic through the change of CPW structure is introduced. The CPW filters with narrow bandwidth are suggested and characterized for their microwave performance using the finitely backed conductor. This structure
7-Pole HTS Bandpass Filter Using New Non-adjacent Coupling of Pseudo-lumped Element Resonators
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1313~1321
This paper presents a novel HTS microstrip pseudo-lumped element resonator for the compact and simple filter design. A 7-pole bandpass filter with quasi-elliptic response is designed and fabricated using non-adjacent couplings between resonators. A seven-pole quasi-elliptic filter is fabricated using double sided YBCO on a LaAlO
substrate with thickness of 0.5 mm and dielectric constant of 23.5. The filter has an insertion loss of 0.8 dB at 20K, a bandwidth of 8 MHz at the center frequency of 1774 MHz, and an attenuation of 33 dB for the cut-off-band of 1 MHz.
Complex Antenna Factors of EMC Monopole Antenna
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1322~1328
This paper presents the characteristics of complex antenna factors of monopole antenna for the measuring time-domain fields above the ground plane. The method of moments with Galerkin's procedure is used to determine the current distribution of the antenna. The monopole antenna with chip resistor is discussed to reduce the reflection at low frequencies. Numerical results show that the magnitude of the complex antenna factor for the monopole with chip resistor is 5.6 dB as large as that of the conventional monopole antenna. The characteristics of the modified complex antenna factor to use the antenna factor are also treated at low frequencies. To verify the theoretical analysis, experimental results are compared with theoretical ones.
Hybrid Fractally Expanded Cross Antenna
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1329~1336
A new fractal geometry of the traveling wave type cross antenna is newly presented. In the conventional type of the traveling wave antenna, the electrical length of the radiating conductor increases as the order of fractal expansion increases. But, increased length of the current path degrades the performance of the antenna from the various loss mechanism of the traveling wave type antenna. To reduce the antenna performance degradation, the new hybrid fractal antenna, which divides the entire fractal structure into some smaller ones and connects each smaller fractal group with a power divider is presented. The secondly, thirdly and fourthly expanded hybrid fractal cross antennas are fabricated and their performances are examined by measurements. Influences of the fractal order to the antenna performance are examined.
Analysis of the Cavity-backed Circular Microstrip Array antenna with Triangular Grid
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1337~1345
In spite of the advantages of lightweight, low profile, and mass productions, microstrip array antenna has inherently the scan blindness problems in case of wide angle scan. And this scan blindness can be overcome by using cavity-backed microstrip radiator. In this paper, we presented the algorithm of analyzing skewed cavity-backed microstrip array and verified the validity of the proposed numerical results with those of reference papers. Finally, we show the effect of cavity-backed and skewed grid array structure.
Radar Vehicle Detector for the Raplacement of the Conventional Loop Detector
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1346~1354
A Novel Technique to Miniaturize Microstrip Antennas with a Locally Non-Homogeneous Substrate Configuration
Lee, Byung-Je ; Kim, Jong-Heon ; Lee, Jong-Chul ; Kim, Nam-Young ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1355~1362
Microstrip antennas are attractive for many applications because of their compact size, low profile, and light weight. Recently, the demand for the miniaturization of the personal communication equipment has been increasing along with the proliferation of personal communication systems. Thus, the development of small antenna has been highly demanded. In this paper, a new technique to reduce the overall dimension of a microstrip antenna with a locally non-homogeneous substrate configuration is proposed. The miniaturized microstrip antenna for a repeater system in a mobile communication cellular band(824~894 MHz) is designed with the proposed technique, and commercialized with low cost, light weight, and small size. Comparison between simulations, based on Agilent Technologies HFSS software, and measurements are provided. The proposed method will be more attractive for a light-weight, small-size, and low-cost microstrip array design. This paper also presents the bandwidth improvement technique for under-coupled microstrip patch antenna with a tuning stub.
Electromagnetic Scattering Resonances on a Periodic Strip Grating on a Grounded Dielectric Slab: Bragg Blazing Phenomena of TM Polarization Case
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1363~1375
The electromagnetic scattering characteristics by a periodic strip grating on a grounded dielectric slab for TM polarization case are examined from the viewpoints of both the reflection grating and the leaky wave antenna problems. Numerical results far two kinds of Bragg blazing (resonance type and non-resonance type) phenomena are given and some discussions on the properties(complex propagation constants, scattering characteristics, and distributions of strip current density) are presented. The comparison of the Bragg blazing phenomena between TM and TE polarization cases are also given in detail.
Design of Fixed Phase Control Circuit of Group Delay Line using Adaptive Vector Control
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1376~1385
The phase characteristic of delay line in feedfarward linearizer has been changed due to variation of operating temperature. In this paper, design method of fixed phase control circuit of group delay line using adaptive vector control is derived. To maintain transfer characteristics of nominal operating temperature, the error correlated signals, which are changed adaptively due to changing of temperature, are added to main signals. The proposed method maintains transfer characteristics under 0.06dB of insertion loss and 0.36
of phase variation in case of 1-tone(880 MHz) and under 0.07 dB of insertion loss and 0.35
of phase variation in case of 2-tones(877 MHz, 882 MHz) for 10dB input power dynamic range and +/-10
phase variation respectively.
A Study on the Temperature Compensated and Linearized Power Detector
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1386~1391
In this paper, the method to linearize the non-linearity of diode and to compensate the characteristics change of diode with the temperature is studied. Square root circuit is used to linearize the non-linearity of diode about the input power, and two identical diodes and OP-Amps, which have variable reference, are used to compensate the characteristic change of diode with the temperature. As the result, designed diode power detector (with the square root circuit and temperature compensation circuit) can detect the output power linearly with the 0.23
0.025V/dBm rate in the case the input power is greater than -6 dBm, and the designed circuit operates stably with no variation in the output data about the temperature change from the room temperature to 8
Design of Sub-Harmonics Pumped Ring Mixer
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1392~1398
In this paper, Sub Harmonic Ring Mixer using Anti-Parallel Diode Pair is studied. Conventional mixers mix LO signal with RF signal and, obtain IF signal from the difference between LO and RF. Sub harmonic ring mixers using APDP mix RF signal with the second harmonic of LO signal, LO frequency needed for conventional receiver is reduced by 1/2.The produced mixer showed 12 dB conversion loss, and 1 dB compression point of IF signal, in respect to RF signal, was found at the 0 dBm RF signal. Isolation LO/IF and LO/RF is 24.6 dB and 22.5 dB respectively. Isolation RF/LO and LO/RF is 32.6 dB and 22.5 dB respectively.
The Exact Field Representation in Cylindrical Cavity Resonators with Concentric Dielectric-rod
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1399~1406
The exact electromagnetic field in cylindrical cavity with concentric dielectric rod is analyzed. Resonant frequency of dielectric loaded cavity is calculated by analyzing the characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. As the result of comparing calculation value and experimental value of resonant frequencies, we know that the field representation of traveling mode is exact.
A Feedforward Linear Power Amplifier using Error Feedback Technique
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1407~1413
This paper presents a feedforward linear power amplifier (LPA) using error feedback technique to achieve low intermodulation distortions(IMD) of power amplifiers for base stations. Especially, the proposed linear power amplifier is applied to feedforward technique combined with error feedback technique, which has no loss of amplifier gain unlike typical feedback technique. The proposed LPA is designed by using HP ADS ver. 1.3, fabricated. When two-tone signals at 1850 MHz and 1851.25 MHz with -7 dBm/tone from synthesizers are injected into the main power amplifier with gain of 28 dB and P1dB of 1W, the proposed LPA could reduce more than 35 dB.
Resolution Enhancement of Spatial Spectrum by a virtually Expanded Array
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1414~1419
In this paper, we propose a resolution enhancement method for estimating direction-of-arrival (DOA) of narrowband incoherent signals incident on a general array. The resolution of DOA algorithm is dependent on the aperture size of antenna array. But it is very impractical to increase the physical size of antenna array in real environment. Therefore we propose the method that increases the aperture size by virtually expanding the sensor spacing of original antenna array and then construct the steering matrix of the virtual array using the proper transformation matrix. Superior resolution capabilities achieved with this method are shown by simulation results in comparison with the standard MUSIC for incoherent signals incident on a uniform circular array.
A Computation of the Resonant Frequencies using Contour Graph Method in the Dielectric-disc Loaded Cylindrical Cavity Resonators
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1420~1427
We described a method to obtain electromagnetic solution and resonant frequencies in dielectric-disc loaded cylindrical cavity resonators. Resonant frequency of dielectric-disc loaded cylindrical cavity resonators is calculated by analyzing the characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. As increasing to height of cavity, we compare the calculated resonant frequency with experimental frequency. The calculated results well agree with the experimental ones. The error between them is 0.2% or 1.6% for the case of the top plate is close to or far from concentric dielectric-disc, respectively.
An Adaptive Predistorter Linearizer Architecture for the DSP Implementation
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1428~1436
An adaptive predistorter linearizer suitable for the DSP implementation is proposed. Predistortion is performed by the DSP instead of the analog predistorter. RLS algorithm is employed for the optimization process to minimize the errors between the predistorter and postdistorter output signals. Computer simulation results for our linearizer show good performance.
Channel Estimation for WLAN System Employing CCK Modulation in Multipath Fading Channels
Cho, Jin-Woong ; Kang, Cheol-Ho ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1437~1443
This paper considers a channel estimation technique in a wireless local area network (WLAN) system with complementary code keying (CCK) signaling over multipath fading channels. This scheme uses the maximum correlator output of RAKE receiver for the extraction of the channel parameters. The performance of the proposed detection technique is compared with that of a noncoherent detection technique, and a significant improvement of performance is observed in terms of the bit error probability.
The Implementation of Group Delay Equalizer and Its Performance Evaluation for Point-to-Point Digital Radio Relay System
Suh, Kyoung-Whoan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1444~1454
The implementation of IF group delay equalizer and its performance are presented for radio relay system applications, and measured results are in good agreement with the simulated ones based upon analytical formulations. For waveguide filter of 40㎒ channel spacing, equalized delay accuracy of about +/- 2.0nsec can be obtained only by constructing 4 stage delay circuits, which provides good performance in system BER curves compared with no filter case, and the difference is less than 1.0㏈ at
BER. So this scheme with simple hardware design can be used for correcting the distorted group delays mainly caused by wavegiude filters. To evaluate the designed group delay equalizer, various simulated and experimental results are shown here in conjunction with STM-1 signal of co-channel 64-QAM digital radio relay system.
Design of Stacked Bow-Tie Antenna for Wireless LAN
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 11, issue 8, 2000, Pages 1455~1461
There are many researches to increase bandwidth of the microstrip patch antenna for wireless LAN. In spite of broad bandwidth, Bow-Tie antenna has disadvantages that are low gain and big size. In this paper, stacked Bow-Tie microstrip patch antenna for wireless LAN is designed in 5.725 ~5.825 GHz band. This antenna has characteristics that are broadband bandwidth, high gain and small size compared with microstrip patch antenna. In simulated results, the return loss is -34.2 dB at 5.78 GHz and bandwidth is 11.345% for VSWR 2:1 and 7.75%for VSWR 1.5:1. In measured results, the return loss is -38.45 dB at 5.78 GHz and bandwidth is 13% for VSWR 2:1 and 5.6% for VSWR 1.5:1. It has 73.16
-3dB beam width and 6.5dB gain.