• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.1-9
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• 2014

In this paper, a reconfigurable polarization patch antenna that uses a Y-shaped feed is proposed. The proposed antenna consists of a square patch, a Y-shaped feeding structure, a PIN diode, and a bias circuit for diode operation. The structural symmetry/asymmetry of the feeding structure is determined by the on/off operation of the PIN diode that inserted into the side of one of the lines of the Y-shaped feeding structure. For the proposed reconfigurable antenna, the two microstrip lines of the feeding structure have the same length when the PIN diode operates in the on state, and the antenna exhibits linear polarization(LP). On the other hand, when the PIN diode operates in the off state, the length of one side line of the feeding structure is relatively shorter than that of the other line. Therefore, the antenna exhibits circular polarization(CP). From the measurement results, it is found that the proposed antenna exhibits good impedance matching and axial ratio. In addition, polarization switching can be easily achieved in the same operating band.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.629-636
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• 2011

This paper presents the design of a novel integrated T-DMB/GPS/Mobile antenna for vehicular application. The T-DMB antenna is designed with a modified meander-type microstrip patch providing linearly a polarized broadside radiation pattern. The GPS antenna is designed with an inserted slot in the patch antenna providing circularly polarized broadside radiation pattern. The Mobile (GSM, AMPS, DCS, PCS, UMTS, etc.) antenna is designed as a modified G-type patch antenna providing multi-band operation. Experimental results indicate that the impedance bandwidth (VSWR 1:2.5) of the proposed T-DMB /GPS/Mobile antenna satisfactorily matches that of the simulation results. The 2D and 3D radiation patterns and gains according to the results of the experiment are also presented and discussed.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.9
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• pp.1285-1291
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• 2013

In this paper, a double circular ring monopole antenna for wideband applications is designed and fabricated. The proposed antenna is based on a planar monopole design, and composed of double circular ring of radiating patches and ground plane to obtain the wideband characteristics. To get the optimized parameters, we used the simulator, Ansoft's High Frequency Structure Simulator(HFSS) and found the parameters that effect antenna characteristics. Using the obtained parameters, the proposed antenna is fabricated. The fabricated antenna is measured at the operating frequencies, and the return loss coefficient, gain, and radiation patterns are determined. The results of measurement, -10dB impedance bandwidth, measured return loss is 4,530 MHz(2,510-7,040 MHz) and antenna peak and average gains for the frequencies are obtained 0.71~3.38 dBi, -3.85~0.3 dBi, respectively. In case of radiation patterns, the proposed antenna displays nearly omnidirectional radiation characteristics in the E-plane, and monopole-like radiation pattern characteristics in the H-plane.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4515-4521
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• 2010

A Yagi antenna, which is a typical directional antenna, has been designed and fabricated as a surveillance sensor. The proposed Yagi antenna satisfies the requirements as a surveillance sensor; impedance bandwidth of 7.2-8.2GHz, maximum gain of 7dBi, and 3dB beamwidth of $60^{\circ}$ in the azimuthal plane. The proposed Yagi antenna is designed with 3 directors and one driven element on a dielectric substrate. Also, a microstrip-to-CPS balun is designed and applied to the proposed antenna for balanced feeding of the dirven element. The performance of the proposed antenna has been verified by comparing the simulation and measurement results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.121-126
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• 2022

This study is about an antenna implemented in the form of a monopole having a hexagonal symmetric pattern by simplifying the modified Hilbert curve fractal monopole structure. The modified Hilbert curve fractal monopole structure was simplified and miniaturized, and the radiator was implemented in a hexagonal symmetrical pattern to improve performance. The dielectric constant of substrate is 4.7, and the total line length with a meander-shaped symmetrical structure is 59 mm. The size of the antenna is 10 mm × 10 mm × 0.8 mm, and the line width is 0.4 mm. The size of the antenna measuring jig is 64 mm × 21 mm × 1 mm. The resonant frequency is 1.57 GHz, and the frequency range is 1.51 to 1.615 GHz. The frequency bandwidth is 105 MHz. As for the antenna gain, the measurement gain of the YZ-plane was 2.32 dBi, and that of the XZ-plane was -1.03 dBi. As a result, we confirmed that antenna miniaturization is possible using a hexagonal symmetric pattern fractal structure. In addition, we confirmed that the antenna performance can be easily improved by changing the structure of the radiator.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.65-71
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• 2023

In this paper, the design, fabrication and verification steps of an electronically scanned array antenna(AESA) for a photonics-based Ku-band FMCW radar system is described. The presented system consists of a transmitter and a receiver respectively, which has a same antenna in the transceiver. The designed antenna has 2×8 array configuration and operates at Ku-band. The VSWR(Voltage Standing Wave Ratio) of each 16-radiators and the coupling power between radiators is measured. Also, in order to minimize the radar system damage because of handover power from the transmitter antenna to the receiver antenna when the transmitter works, the isolation between the transmitter antenna and the receiver antenna is optimized by test. As a result, beamwidth, side lobe level and beam steering characteristic are obtained by synthesizing each radiator pattern measurement data after each beam pattern of 16-radiators is measured in the near-field chamber.

• Journal of Communications and Networks
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• v.1 no.3
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• pp.166-181
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• 1999

The object of this paper is to investigate the influence of antenna pattern on indoor radio channel characteristics. Different from previous works where this analysis was carried out at a fixed frequency using different antennas, in the present paper (where measurements were taken in a wide frequency range) the variation of the radiation pattern was caused by two factors: the change of the radiation pattern when the same antenna was used at different frequenicies and the use of different type of antennas. To carry out this analysis, frequency domain measurements of the indoor radio channel at 1 GHz, 5.5 GHz, 10 GHz and 18 GHz were collected. Measurements were taken using a network analyzer. Serveral re-alizations of the channel transfer function were obtained varying, for each measurement, the positon of the transmitter and keep-ing the receiver fixed. Estimate of the channel impulse response was obtained from the Inverse Fourier Transform (IFT) of the fre-quency response. The measurements were performed in an office enviroment with mostly metallic walls and inner separations. The obtained data were elaborated to obtain the power versus distance relationship, the Cummulative Distribution Functions(CDFs) of rms Delay Spread(DS) and of the 3 dB frequency correlation band-width. Finally, the 3 dB width of the frequency correlation func-tion has been empirically related to the inverse of the rms DS of the impulse response.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.7
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• pp.1-8
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• 1999

A complete electromagnetic simulation for a ground-penetrating radar(GPR) is implemented by employing 3-dimensional dispersive finite-difference time-domain(FDTD) method. The presented simulation model includes the cavity-backed bow-tie antennas, which are terminated by resistors. And an equivalent cirvuit consisting of the input impedance of the antenna and the characteristic impedance of the feed line is used to calculate the response in the receiving antenna. Actual emasurements of a GPR system including our manufactured bow-tie antenna pair are performed just above dry sand contained in a PVC tank. It is confirmed that the FDTD simulation results agree well with the actual measurement data.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.69-80
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• 2012

In this paper, we studied the time-domain measurement and analysis techniques using a network analyzer for characterization UWB antenna link radiating impulse signal. For this purpose, we developed the CZT(Chirp z-Transform) algorithm which has characterized zoom-in function and transformed the acquired data from network analyzer to time domain format. Using the CZT algorithm, we proves that it would be better efficient and more faster than the DFT for analyzing the waveform and also be able to zoom-in the arbitrary region.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.265-266
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• 2008

The objective of this paper is to effectively detect partial discharges in XLPE power cables. In this field, we have been usually applied several sensors for such partial discharges. This study used a type of beyond compare antenna based on the influence of background noises. Also, we designed a new structure that is able to easily apply in the adhesion of planar patch types for XLPE power cables in measurement sensitiveness elevation. A high frequency simulation tool (CST-MWS) was applied to the antenna used in this study, and it was used to evaluate certain characteristics. We fabricated an antenna using the simulation data obtained from a specific test. After checking the sensitivity of this Planar Patch Sensor in the Lab, it was tested in an actual site. This paper analyzed the data as a part of time and frequency domain using an oscilloscope and spectrum analyzer, respectively.