• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.1 s.92
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• pp.9-18
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• 2005

This paper presents an antenna for US-PCS band indoor repeaters with enhancement of isolation. In common repeaters require an enough isolation to reduce the interferences between transmitted and received signals. Thus, it is investigated to improve front-to-back ratio of IBD(Integrated Balun Dipole) antenna which has a good linear polarization with a cavity or multi-cavity by using polarization diversity and aperture matching method. From the simulated and measured results, the antenna realized by using polarization diversity and aperture matching method has a VSWR below 1.5, gain over 8 dBi and enhanced isolation of 15$\~$24 dB in US-PCS band.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.2
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• pp.21-27
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• 2014

In this paper, a planar sleeve monopole antenna for indoor digital TV reception is presented. The antenna has broadband property with the planar monopole and ground of sleeve. Sleeve monopole and ground conductors of the antenna are on the same plane, and exited through CPW feeding. Sleeve monopole and ground of proposed antenna exist on coplanar plane, and excite as CPW. It used FR4 epoxy dielectric substrate of ${\varepsilon}r=4.4$, and the size is $20[mm]{\times}170[mm]{\times}1.6[mm]$ dimension. So the internal antenna is suitable. The measurement results of the fabricated antenna, return loss is larger than -10 [dB] in 470~806 [MHz]. Maximum gain is 0.59 [dBi] on E-plane at 810 MHz and 1.70 [dBi] on H-plane at 640 [MHz]. Radiation pattern is about the same that of dipole antenna at all frequency.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.9
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• pp.963-968
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• 2008

A new method to deal with GPS indoor positioning by means of time synchronized switching GPS repeater has been developed by authors[1]. But the developed indoor positioning system has problems. Therefore, we proposed a method for indoor positioning using GNSS Repeater-Assisted. To solve the 3-dimensional user's position, the 4 or more retransmission antennas are needed in the previously proposed methods. If a GPS repeater periodically transmits the signal like as pseudollite, the information for assisting an acquisition and tracking can be informed to receiver. Then, the user position can be calculated using the induced weak signal. The advantage of the proposed algorithm is use of only 1 re-transmission antenna because the re-transmitted signal are not used for positioning but used for assisting an acquisition and tracking weak signals induced indoor. We analyze the propose algorithms through the experiment and performed the test of feasibility.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1492-1497
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• 2017

In this paper, a design method for a CPW-fed wideband loop antenna for indoor digital TV applications is studied. The proposed loop antenna consists of a square loop and two circular sectors which connect the loop with central feed points, and the CPW feed line is inserted in the lower circular sector. The CPW feed line is designed to match with the 75 ohm port impedance for DTV applications, and the ground slots are etched in order to improve the impedance matching in the middle frequency region. The effects of the gap between the circular sectors and the location and dimension of the ground slots on the input reflection coefficient and gain characteristics are examined to obtain the optimal design parameters. The optimized antenna is fabricated on FR4 substrate, and the experiment results show that it operates in the frequency band of 463-1,280 MHz for a VSWR < 2, which assures the operation in the DTV band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.9 s.100
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• pp.926-931
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• 2005

In this paper, the printed-sleeve monopole antenna which has the small size and the broadband characteristics, is presented and its radiation characteristics are investigated. To conform the broadband characteristics of the proposed antenna, the experimental antenna is designed, fabricated, and its radiation characteristics are measured in PCS band (1.75 GHz${\~}$1.87 GHz). It is shown that the designed antenna has the non-directional pattern in the horizontal plane, the directional pattern in the vertical plane, VSWR less than 1.5, and gain in 2.14 dBi${\~}$3.4 dBi. From these results, the proposed antenna is conformed as a broadband antenna which can be used for the mobile communication indoor antenna extensively.

• 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

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.2
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• pp.302-311
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• 1999

In this paper, in order to suggest an optimal polarization diversity composition method in indoor radio wave propagation environments, the variation of the cross polarization discrimination(XPD) was theoretically analyzed by a computer simulation and compared to the actual measured data. From the results, it can be seen that the cross polarization discrimination of the case, a circularly polarized antenna was used at the transmitting end as well as the vertical and horizontal polarized antenna branches were used at receiving end (CV-CH), is lower than that of the case, horizontal polarized antenna at the transmitting end as well as the horizontal and vertical polarized antenna branches at the receiving end(HH-HV), and that of the case, vertical polarized antenna at the transmitting end as well as the vertical and horizontal polarized antenna branches at the receiving end(VV-VH). In this paper, to get more effective CV-CH polarization diversity composition, the amount of cross polarization discrimination values at the signals received by horizontal polarized antenna is compensated and the polarization diversity effect through the cumulative probability distribution is estimated. From the evaluation results, it was found that the polarization diversity effect was better at the compensated case than at the uncompensated case. On the other hand, it can be known that the polarization diversity effect is getting better as the cross polarization discrimination values are getting lower, and also be known that the effect can be improved if a transmitting antenna is composed of the ellipse polarized antenna by adjusting the axial ratio of the circularly polarized antenna and, a receiving antenna is made up of the vertical and horizontal polarized antenna branches.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.30-33
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• 1998

In this paper, 60 GHz indoor broadband wireless channels are measured with various configurations in a typical coffice environment. Mesurements are taken at nine positions of the room and the base-station antenna is placed either at the center or at an edge of the measurement room, and the remote-station antenna is either sharp beam or broad beam type. The rms delay spread(RDS) and normalized received power (NRP) are estimated from the measurements. Bit error rate simulations are performed using impulse responses for two measurement positions with QPSK/DQPSK OFDM modulation. Using sharp beam antenna results in superior performances than using broad beam antenna in terms of both bit error rates (BER) and NRP penalty. Also, placing the bese-station antenna at the center is superior to placing it at an edge in terms of BER and NRP.

• Journal of Electrical Engineering and information Science
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• v.3 no.1
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• pp.117-125
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• 1998

In this paper, in order to investigate the fading reduction effect of narrowband and broadband signals in an indoor multipath propagation environment, both the received narrowband signal while a vehicle unit in motion and the frequency sweeped broadband signal received by vertical polarized antenna, horizontal polarized antenna and circularly polarized antenna are analyzed. Specifically, in order to evaluate polarization diversity effect, we examined the difference of fading reduction effect between the polarization diversity reception and the space diversity reception. Using the correlation coefficient and correlation graph for the polarization diversity branches, the diversity effect is evaluated. And also, using the cumulative distribution for the received signal strength simulated by diversity reception, the diversity effect is also estimated. From the evaluation results it was found that the polarization diversity which use a circularly polarized antenna at the transmitting end and the vertical and horizontal polarized antenna branches at the receiving end is markedly excellent.