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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 18, Issue 12 - Dec 2007
Volume 18, Issue 11 - Nov 2007
Volume 18, Issue 10 - Oct 2007
Volume 18, Issue 9 - Sep 2007
Volume 18, Issue 8 - Aug 2007
Volume 18, Issue 7 - Jul 2007
Volume 18, Issue 6 - Jun 2007
Volume 18, Issue 5 - May 2007
Volume 18, Issue 4 - Apr 2007
Volume 18, Issue 3 - Mar 2007
Volume 18, Issue 2 - Feb 2007
Volume 18, Issue 1 - Jan 2007
Selecting the target year
A Study on GSM Handset Structure for Radiation Power Optimization under Head Phantom
Yang, Bu-Young ; Kim, Jung-Min ; Yook, Jong-Gwan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 689~697
DOI : 10.5515/KJKIEES.2007.18.7.689
This thesis suggests ways on how to enhance handset radiation power under head phantom condition. Generally, peak EIRP(Effective Isotropic Radiated Power) is used to measure the radiation performance. TRP is more effective to represent indication of mobile radiation performance in the field than EIRP. In this case, we measure the TRP as an index of radiation power. The factors which effect TRP are antenna length, antenna position, folder angle and ground connection method. More detailed analysis is performed over these items. Significant item is ground connection method between main PCB and folder GND. Using the FPCB we connect main GND to folder GND through the hinge near the antenna. The result is that TRP attenuation is decreased about 5 dB under head phantom condition.
10-Bit Full-Coverage Impedance Tuner Using a Directional Coupler and PIN Diodes
Lee, Dong-Kyu ; Lee, Sang-Hyo ; Kwon, Young-Woo ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 698~703
DOI : 10.5515/KJKIEES.2007.18.7.698
In this paper, a novel impedance tuner using a directional coupler is proposed. The design topology is analyzed by signal flow graph(SFG) and shows advantages compared with conventional single and double stub methods from the view points of easy implementation and wide tuning range, respectively. This impedance tuner consists of ten switches and its
tuning points are distributed uniformly on the whole Smith chart. The measured maximum magnitude of the reflection coefficient is 0.9. And the fabricated impedance tuner has a wide bandwidth from 1.8 to 2.2 GHz. Using this impedance tuner, we did a load-pull measurement of a power transistor.
A Design of CPW Band-Pass Filter with Rejection Band for Ultra-Wideband System
No, Jin-Won ; Hwang, Hee-Yong ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 704~709
DOI : 10.5515/KJKIEES.2007.18.7.704
In this paper, a CPW band-pass filter with a rejection band is proposed for UWB(Ultra-Wideband) communication systems. The proposed filter has a band-pass characteristic of wide-band by inserting only a slot in
transmission line. To obtain the band-rejection function at WLAN frequency band(
), the designed filter is combined with folded slot resonators on the ground plane of the CPW structure. The fabricated CPW band-pass filter shows a compact size of
, a wide passband of 2.8 GHz to 9.8 GHz and the narrow stop-band of 5.15 GHz to 5.71 GHz for 3-dB bandwidth. Also, the measured group delay is less than 400 psec throughout the operation frequency band except the rejection band.
Realization of Power Amplifier Using a Harmonic Rejection Circuit
Song, Byoung-Jin ; Kim, Jae-Hyun ; Go, Min-Ho ; Park, Hyo-Dal ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 710~716
DOI : 10.5515/KJKIEES.2007.18.7.710
In this paper, I study on the realization of 900 MHz 1 W power amplifier using a harmonic rejection circuit. The proposed harmonic rejection circuit has improved the harmonic rejection characteristic and overcoming the problems related with frequency reproducibility on the microstrip line. The proposed power amplifier, fabricated by the type of hybrid with the epoxy PCB, was composed of driver stage and power amplifier stage with harmonic rejection circuit. The fabricated power amplifier shows -24 dBc and -30 dBc of harmonic rejection characteristic at 2nd and 3rd harmonic compared with that is not used, respectively and it could be replace the filter located between an output stage and an antenna.
ISAR Imaging of a Real Aircraft Using KOMSAR
Kim, Kyung-Tae ; Jeong, Ho-Ryung ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 717~722
DOI : 10.5515/KJKIEES.2007.18.7.717
Inverse synthetic aperture radar(ISAR) images represent two-dimensional(2-D) spatial distribution of electromagnetic scattering phenomenology against a target. Hence, they are usually used in the areas of automatic target recognition (ATR) or non-cooperative target recognition(NCTR), identifying a target using radar in a long distance. This paper makes use of Korea Miniature Synthetic Aperture Radar(KOMSAR) to generate ISAR images of a real and maneuvering aircraft. The data obtained from KOMSAR are processed to eliminate phase errors due to motion of a target, with the use of entropy-based ISAR autofocusing technique. Results show that we can successfully obtain ISAR images of a real aircraft, and the success of experiments implies that a significant step toward ATR using radar has been established.
W-CDMA 30 Watts High Power Amplifier Using Anti-Phase Intermodulation Distortion Linearization Technology
Kang, Won-Tae ; Do, Ji-Hoon ; Chang, Jeong-Seok ; Hong, Ui-Seok ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 723~730
DOI : 10.5515/KJKIEES.2007.18.7.723
This paper shows how the ACLR of power amplifier can be reduced by using Anti-phase IMD linearization technique which generate anti-phase IMD in the driver stage compare to output stage's IMD. And design process proposed. From the experimental result of W-CDMA 4FA input signal, this amplifier has ACLR -55 dBc@5 MHz offset at 30 watts average power. Compare to optimum matching technique to get maximum power gain, this technique has been improved ACLR by 12 dBc. Also this amplifier meets 50 watts average output power amplifier specification in domestic market.
A Study on the Reduction of RFID System's Interrogation Range with Respect to Reader Interference
Lee, Yoon-Deock ; Kim, Do-Yun ; Yoon, Hyun-Goo ; Yook, Jong-Gwan ; Jang, Byung-Jun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 731~738
DOI : 10.5515/KJKIEES.2007.18.7.731
Recently UHF RFID system has drawn a great deal of attention because of its potential to revolutionize supply chain management. In this article, RFID reader-to-reader interference is analyzed in terms of interrogation range. For evaluating RFID interference quantitatively, the new figure-of-merit, IRRR, is defined. In order to show the usefulness of IRRR, calculated IRRR is verified by measurement using two RFID readers and a tag in multiple-reader environment. IRRR can be referred to an important design parameter to analyze more complex interfering problems in actual RFID system deployments.
Analysis of Periodic Stepped Impedance Ring Resonator by the Effect of Step Perturbation and Application of Dual-Mode Bandpass Filter
Lee, Ju-Gab ; Lee, Wu-Seong ; Ryu, Jae-Jong ; Moon, Yeon-Kwan ; Kim, Ha-Chul ; Choi, Hyun-Chul ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 739~747
DOI : 10.5515/KJKIEES.2007.18.7.739
Dual-mode bandpass filter was designed by using periodic stepped impedance ring resonator with step perturbation. The periodic stepped impedance ring resonator has the effects of size reduction and
harmonic suppression by changing characteristic impedance ratio. The perturbation for dual-mode generation was also easily controlled by characteristic impedance ratio, and the variation of dual-mode resonant frequencies and attenuation pole frequencies were analyzed by the effect of step perturbation. Chip capacitors were used for input/output coupling, and the variation of center frequency by the coupling capacitance and step perturbation was also considered. From the results, two types of 2 GHz dual-mode bandpass filter were fabricated in size of
, those have different attenuation poles and bandwidths. The measured results of proposed bandpass filters showed a good agreement with the calculated estimations, and those have insertion loss of 2.52, 0.52 dB and 3 dB bandwidth of 4.03, 15.02 %, respectively.
Design of an SIR BPF by a Novel EM Tuning of Individual Resonators
Yang, Seong-Sik ; Yeom, Kyung-Whan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 748~756
DOI : 10.5515/KJKIEES.2007.18.7.748
In SIR filter, fringing capacitances and discontinuities yield a distorted frequency response from those expected by design formulas, especially in higher frequencies. In this paper, a procedure is presented in order to compensate for fringing capacitances and step impedance discontinuities by EM simulation for a 5th order SIR filter. This method propose the procedure of tuning the coupling and the length of individual resonator by EM simulation. For the filter composed by the tuned resonators, no further tuning is required. The procedure is experimentally justified by comparing the measured data of the fabricated filter with the simulation results.
Performance Analysis of OFDM Communication System with the IQ Imbalance and Phase Noise
Kim, Sang-Kyun ; Ryu, Heung-Gyoon ; Kang, Byung-Su ; Lee, Kwang-Chun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 757~765
DOI : 10.5515/KJKIEES.2007.18.7.757
OFDM system is an excellent high speed transmission method but it is seriously sensitive to the phase noise and IQ imbalance. Therefore, in this paper, we analyze the communication performance of the OFDM communication system with IQ imbalance and phase noise. Phase noise's variance can be calculated by integral calculus of phase noise power spectrum. From simulation results, it can be shown that the BER performances show different change according to the phase noise variance and IQ imbalance amount. When amplitude imbalance is
=0.2; 0.3; 0.4 and phase imbalance is
, and distribution of phase noise is
, BER is degraded by 2.88 dB, 3.61 dB, 4.09 dB in
in the respect of the SNR penalty.
Design of Cooperative M-1-1 Protocol Using OFDM to Increase Spectrum Utilization in WSN
Hwang, Yun-Kyeong ; Kong, Hyung-Yun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 766~773
DOI : 10.5515/KJKIEES.2007.18.7.766
Conventional wireless sensor network(WSN) has limited power and bandwidth. In order to develop multimedia sensor technology, high data rate communication systems are required. Cooperative communication system can help to decrease power consumption through spatial diversity. In cooperative transmission, one partner node assists one sensor node to transmit their data to destination. Instead of using M partners for M sensor nodes, we propose 1 partner for M sensor nodes. Proposed protocol offers similar diversity order as conventional one with much less bandwidth and hardware. It is able to almost reduce scattered nodes interference using orthogonal sub-carriers. In addition, we examined a power allocation between sensor nodes and relay that optimize the system performance.
Antenna-Diplexer Module for Cellular/SDMB Band Using LTCC Technology
Ha, Jeung-Uk ; Chang, Ki-Hun ; Yoon, Young-Joong ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 774~783
DOI : 10.5515/KJKIEES.2007.18.7.774
This paper presents an integrated packaging antenna-diplexer module for wireless communication systems in the Cellular and SDMB band. The design and the realization of the proposed one are experimentally analyzed and discussed. It consists of a dual-resonance antenna and a diplexer with a multi-layer LTCC(
) technology with integration capability and low loss. The dual-resonance antenna of the proposed module has the meander line structure for size reduction and has the shorting structure of an inverted F antenna to achieve good impedance matching. The diplexer of the proposed module was designed with the combination of low pass filter(LPF) and high pass filter(HPF). Decreasing the mutual interference between them provides a high isolation characteristic. The proposed antenna-diplexer module with dimensions of
operates within a range from 813 MHz to 902 MHz for the cellular band and from 2,586 MHz to 2,655 MHz for the SDMB band. And the measured gain of the fabricated module is -1.96 dBi for Cellular band and -5.43 dBi for SDMB band. The parameters for the antenna-diplexer module are investigated and the several performances are discussed.
A Study on the Intenna Based on PIFA with Multi Element
Lim, Yo-Han ; Chang, Ki-Hun ; Yoon, Young-Joong ; Kim, Yong-Jin ; Kim, Young-Eil ; Yoon, Ick-Jae ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 784~795
DOI : 10.5515/KJKIEES.2007.18.7.784
In this thesis, the Multi element antenna with wideband and enhanced gain characteristic is proposed to operate at both frequency range from 824 MHz to 896 11Hz for the CDMA and frequency range from 908.5 MHz to 914 MHz for the RFID band. The proposed antenna has tile size of
in order to put it in the A model of S company and each element of the proposed antenna is folded to obtain the minimum size. To obtain the antenna with wideband and high gain characteristic, the radiator of the antenna is divided into 4 elements. As a result, bandwidth of the proposed antenna become broader and lower center frequency is appeared due to increased and lengthened current path. Moreover, the enhanced gain characteristic is verified because divided element structure that induct uniform current distribution can get increased antenna efficiency. To attain more uniform current distribution, modified structure of the feeding point that can deliver currents directly is designed. The antenna that alters the feeding structure has higher gain value. Each element is folded to increase the current paths considering the current directions to attain the miniaturization of the antenna. To measure the handset antenna, the handset case must be considered. Even though antenna is designed for predicted characteristic, the resonance frequency is shifted and antenna gain is deteriorated at predicted frequency while antenna is set in the handset case. 1.08 GHz of the resonant frequency is determined after frequency shift from 150 MHz to 200 MHz is confirmed and the maximum gain is measured as 3.1 dBi while antenna is not set in the handset. In case handset case is considered, the experimental results show that the impedance bandwidth for VSWR<2 is from 0.824 GHz to 0.936 GHz(110 MHz). This result appears that the proposed antenna can cover both CDMA and RFID band at once. The measured gain is from -3.4 dBi to -0.5 dBi and it has omni-directional pattern practically.
A Design of Novel Compact Microstrip Bandstop Filters Based on Split-Ring Resonators and Spiral Resonators
Lee, Jong-Hyuk ; Oh, Young-Chul ; Myung, Noh-Hoon ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 796~808
DOI : 10.5515/KJKIEES.2007.18.7.796
In this paper, two novel compact microstrip bandstop filters using complimentary split ring resonators(CSRRs) and spiral resonators is proposed. The first one is the bandstop filter using an array of CSRRs etched on the center line of a microstrip. The bandstop is due to the presence of negative effective permittivity and positive permeability near resonant frequency which prevent the wave propagation. The second on is the bandstop filter using an array of spiral resonators etched on the center line of a microstrip. The bandstop is due to the self-resonance of spiral circuit. We have achieved controllable resonance frequency and bandwidth, super compact dimension, low insertion losses in the passband and high level of rejection in the stopband with sharp cutoff. The electrical sizes of two proposed filter are very small. Additionally, they can be easily fabricated and compatible with MMIC or PCB technology.
A Low Insertion Loss CBFGCPW-Microstrip Transition and Its Application to MIC Module Integration
Lim, Ju-Hyun ; Yang, Seong-Sik ; Yeom, Kyung-Whan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 809~818
DOI : 10.5515/KJKIEES.2007.18.7.809
Generally, carriers on which microwave circuits are mounted are used as building blocks of MIC module for the convenience of MIC assembly and the unit module characterization. However the interconnection of the microstrip-based carriers by wire bonding causes the serious problem of mismatch and results in the higher insertion loss as frequency becomes higher. The gap and the depth between carriers are considered as the main reason of the degradation. The CPW can be the solution to cope with such problem considering its field are dominantly concentrated on the top plane. In this paper, we propose and demonstrate the CBFGCPW to microstrip transition with the low insertion loss that can be applied without causing the MIC carrier interconnection problem.
Numerical Computation of the Backscattering Coefficients of Rice Fields Using the Impedance Boundary Condition, Moment Method and Monte Carlo Method
Hong, Jin-Young ; Oh, Yi-Sok ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 819~827
DOI : 10.5515/KJKIEES.2007.18.7.819
A numerical algorithm for estimating precise backscattering coefficients of rice fields is proposed and its accuracy is verified in this paper. After a bunch of rice plants above water surface is modeled with a bunch of randomly oriented lossy dielectric bodies above an impedance surface and the equivalent volume currents of the lossy dielectrics are computed using the moment method. Then, the scattered fields of a rice field with many bunches are computed with a Monte Carlo method, and consequently the backscattering coefficient of the rice field is computed for various incidence angles and polarizations. Finally, the backscattering coefficient of a rice field is measured at 1.85 GHz using an R-band scatterometer system, and these experimental data are used to verify the numerical algorithm proposed in this paper. It is found that the numerical computation results agree well with the measurement data.
A Small Monopole Antenna with Novel Impedance Matching Structure
Kim, Dong-Jin ; Min, Kyeong-Sik ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 828~833
DOI : 10.5515/KJKIEES.2007.18.7.828
A small monopole antenna with a novel impedance matching structure is proposed in this paper. The proposed antenna is designed for W-LAN(IEEE 802.11b). The antenna design concept is based on a
folded monopole antenna with a self-impedance matching structure. The size of the proposed antenna is smaller than the resonant length, thus the impedance at the terminal of the antenna becomes very capacitive. To compensate fur this impedance mismatching, the proposed antenna employs a novel self-impedance matching structure. The self-impedance matching structure is located on the top of the antenna; it improves the impedance matching and ultimately the efficiency of the antenna. The measured results of the proposed antenna show reasonable agreement with prediction.
A Bandstop Filter with Improved Slope Characteristics Using C-DGS(Coupled-Defected Ground Structure)
Jung, Sang-Woon ; Lim, Young-Kwang ; Lee, Hai-Young ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 834~838
DOI : 10.5515/KJKIEES.2007.18.7.834
A coupled-defected ground structure(C-DGS) having closely-located DGS cells is proposed for high performance bandstop filter applications. The negative coupling of ground currents between adjacent DGS cells greatly improves the stopband characteristics. We have measured the attenuation slope of 110.8 dB/GHz and -20 dB rejection band from 3.8 GHz to 15.5 GHz. Compared to the double-plane BSF, the proposed BSF improved the sharp cutoff response 7.6 times. We expect the C-DGS be helpful to improve the performance of DGS application circuits and also to extend the possible DGS applications.
Dual-Band Feedforward Linear Power Amplifier Using Equal Group Delay Signal Canceller
Choi, Heung-Jae ; Jeong, Yong-Chae ; Kim, Hong-Gi ; Kim, Chul-Dong ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 7, 2007, Pages 839~846
DOI : 10.5515/KJKIEES.2007.18.7.839
In this paper, the first attempt to design a novel structure of dual-band feedforward linear power amplifier(FFW LPA) was presented. Up to now, primary technical difficulty has been the extension of the conventional signal canceller to the dual-band operation. Therefore, we propose the design technique of the dual-band equal group delayed carrier canceller, the dual-band equal group delayed intermodulation distortion(IMD) canceller and the dual-band FFW LPA. The operation frequency bands of the implemented dual-band FFW LPA are digital cellular(
MHz) and IMT-2000(
GHz) band, which are separated about 1.26 GHz. With the high power amplifier of 120 W PEP for commercial base-station application, IMD cancellation loop shows 20.45 dB and 25.04 dB loop suppression at each band of operation for 100 MHz. From the adjacent channel leakage ratio(ACLR) measurement with CDMA IS-95A 4FA and WCDMA 4FA signal, we obtained 16.52 dB improvement at the average output power of 41.5 dBm for digital cellular band, and 18.59 dB improvement at the average output power of 40 dBm for IMT-2000 band simultaneously.