• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.430-432
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• 1988

Radiation admittance of the rectangular microstrip antenna is calculated by using equivalent ${\pi}$-network parameters of the slit in the wall of the parallel plate waveguide filled with homogeneous dielectric. Using equivalent transmission line model, return loss is calculated and compared with experimental result. Calculated values for the return loss show good agreement with experimental values.

• Journal of electromagnetic engineering and science
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• v.17 no.2
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• pp.51-56
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• 2017

This study proposes a modeling process of equivalent terrains to reduce the computational load and time of a full-wave electromagnetic (EM) simulation. To verify the suitability of the proposed process, an original terrain model with a size of $3m{\times}3m$ is equivalently quantized based on the minimum range resolution of a radar, and the radar image of the quantized model is compared with that of the original model. The results confirm that the simulation time can be reduced from 407 hours to 162 hours without a significant distortion of the radar images, and an average estimation error of the quantized model (20.4 mm) is similar to that of the original model (20.3 mm).

• Journal of electromagnetic engineering and science
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• v.2 no.1
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• pp.11-15
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• 2002

In this paper, we have proposed the new configuration of wideband antenna using CPW fred lines. The proposed antenna has CPW feed lines and U-slot to achieve wade bandwidth with good impedance matching. The use of CPW feed line can decrease the number of substrates. It is compared with the conventional antenna find by a microstrip fled line. The parameters of CPW fred lines were studied by using the quasi-static approximation which is based on the conformal mapping method. The analysis of CPW discontinuities such as the tapered-step structure and the open ended gap were studied by using the quasi-static approximation which is based on the boundary element method. Also, the equivalent circuit model of multi-layer antenna were proposed using the cavity model. Experiment results of the proposed antenna 7how wide-bandwidth characteristics and good radiation patterns in passband.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.727-732
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• 2008

Recently, according to the increase of using the microwave equipments, the interests in effects on human body have been also increased. For example, there have been many researches on making the standard the specific absorbing ratio (SAR) caused by mobile phones. However, it is needed to study on the induced current on human body caused by HF(Hight Frequency) band which can deeply penetrate the human body. Especially, since the RFID systems are applied to the transportation card and the library, it is hooded to research on the effect on human body exposed to the radiated power from the RFID system. In this paper, we designed a cylindrical monopole antenna model of human body exposed to 13.56 MHz RFID system, which can model the induced current on human body. To verify the proposed equivalent antenna model, we compared the induced currents between human body and the equivalent antenna model.

• ETRI Journal
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• v.27 no.2
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• pp.227-230
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• 2005

A specific anthropomorphic mannequin (SAM) model was used to investigate the relation between local specific absorption rate (SAR) and head size. The model was scaled to 80 to 100% sized models at intervals of 5%. We assumed that the shell of the SAM model has the same properties as the head-equivalent tissue. Five handsets with a monopole antenna operating at 835 MHz were placed in the approximate cheek position against the scaled SAM models. The handsets had different antenna lengths, antenna positions, body sizes, and external materials. SAR distributions in the scaled SAM models were computed using the finite-difference time-domain method. We found that a larger head causes a distinct increase in the spatial peak 1-voxel SAR, while head size did not significantly change the peak 1-g averaged-SAR and 10-g averaged-SAR values for the same power level delivered to the antenna.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.2
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• pp.364-372
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• 1994

Theoretical method for analyzing the radiation pattern of cross-type 5-patch rectangular microstrip antenna is presented. The equivalent circuit of the array antenna is represented by the conventional transmission line model and the radiation admittance derived from the equivalent circuit of the slitted parallel-plate waveguide filled with a dielectric. The calculated results for the radiation pattern are compared with the measured values.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.129-135
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• 2018

This paper proposes a design of small controlled reception pattern antenna (CRPA) arrays using circular microstrip loops with frequency-insensitive characteristics. The proposed array consists of seven identical upper and lower circular loops that are electromagnetically coupled, which results in a frequency-insensitive behavior. To demonstrate the feasibility of the proposed feeding mechanism, the proposed array is fabricated, and its antenna characteristics are measured in a full-anechoic chamber. The operating principle of the proposed feeding mechanism is then interpreted using an equivalent circuit model, and the effectiveness of the circular loop shape is demonstrated by calculating near electromagnetic fields in proximity to the radiator. The results confirm that the proposed feeding mechanism is suitable to have frequency-insensitive behavior and induces strong electric and magnetic field strengths for higher radiation gain in extremely small antenna arrays.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.2
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• pp.139-146
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• 1996

In this paper, the total electric field antenna in the small loop and aperture plane structure to load a capacitance on transformed QMSA(Quarter-wavelength Microstrip Antenna) from MSA(Microstrip Antenna) is proposed, and the total electric field is shown that the calculated value is agreed resonably with experimental value. Itis a smalled antenna of the radiation element and ground plane with equal width. The designed and manufactured antenna can receive borth vertically and horizontally polarised waves to operating frequency of 1.5GHz; therefore this is available as a smalled antenna for wireless telephones and will be quit useful for indoor communication. Also, antenna's equivalent circuit with transmission line model is designed to find more accurate resonant frequency and is calculated return loss value. The calculated value is agreed resonably with experimental value.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.637-640
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• 2006

In this paper, a microstrip antenna with a small loop consisting of the left and right parallel plate to load capacitor is proposed. It is obtained the improved small size than the antenna of the transformed Uh and the antenna of the left and right parallel plate to load capacitor on QMSA. Equivalent circuit of transmission line model is designed to find more accurate resonant frequency. Also, the designed and fabricated antenna can receive both vertically and horizontally polarized waves to operating frequency of 1.5GHz. Therefore proposed antenna is available as a small antenna for wireless communication and will be quite useful for indoor communication

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.35-40
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• 1989

In this paper, a new method which simultaneously gives the radiation conductance and susceptance of the rectangular microstrip patch antenna. This solution is derived from the load admittance of the equivalent ${\pi}-$network circuit of the slitted parallel-plate waveguide filled with homogeneous dielectric. Our theoretical results for the radiation admittance are compared with other theoretical results. Also, our theoretical return loss and resonant frequency which are calculated by use of the equivalent transmission line model are in fairly good agreement with the experimental results.