• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.175-180
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• 2015

In this paper, GPS / GLONASS receiving a small active antenna is proposed. A microstrip patch antenna which supports dual-band (GPS and GLONASS) was optimized. The antenna size is $13{\times}13{\times}3.6mm$. The jig was changed to confirm the proposed antenna characteristic size, was adjusted to feed gap of the patch antenna, it was confirmed by change in LNA shield case or not. The antenna jig size is $65.6{\times}13{\times}0.8mm$. The maximum gain of the GPS band is 3.78dBi, the maximum gain of the GLONASS bands is 4dBi. To amplify the Satellite reception signal level, one-stage low noise amplifier(LNA) was designed. The LNA chip was using the BGA715 N7, the LNA gain is 19.9dB. The utilization possibility of the GPS / GLONASS receiving a small active antenna could be confirmed according to compare and analyze the simulation and measurement data.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1656-1658
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• 1998

This paper deals with a measurement system of a distance between lightning strokes and observatory station and spectrum analysis of electric fields radiated from lightning discharges. The distance measurement system, which consists of a loop type magnetic field sensor, a microphone and one chip microprocessor, is connected to a personal computer through RS232 port to acquire and process the data. This system is to use a difference of propagation velocity between an electromagnetic wave and a sonic wave produced by lightning discharge. Also, an electric field waveform and a frequency spectrum were investigated by an electric field measurement system with a hemisphere antenna and a spectrum analyzer with a biconical antenna and a log-periodic antenna, respectively. The results would be used as a basic reference to protect the power systems and electric circuits from lightning overvoltages.

• Electrical & Electronic Materials
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• v.10 no.5
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• pp.492-499
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• 1997

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.6
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• pp.628-636
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• 2014

This paper describes the design and analysis of five-element planar array antenna of an anti-jamming satellite navigation system. We propose a design of multi-layer patch antenna for Global Positioning System(GPS) $L_1/L_2$ dual bands. The proposed antenna has two ports feeding network with a hybrid chip coupler for a broad bandwidth with Right-Handed Circular Polarization(RHCP). The measurement results show the bore-sight gains of 1.10 dBic($L_1$) and 0.37 dBic($L_2$) for the center element. The bore-sight gains of an edge element are 0.99 dBic($L_1$) and -0.57 dBic($L_2$). At a fixed elevation angle of $30^{\circ}$, antennas show average gains of -2.08 dBic ($L_1$) and -5.33 dBic($L_2$) for the center element, and average gains of -0.40 dBic($L_1$) and -2.09 dBic($L_2$) for the edge elements. The results demonstrate that the proposed array antenna is suitable for anti-jamming applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.130-136
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• 2014

This paper reviews the research on silicon based phased array system operating from microwave to millimeter wave frequencies. First, the design of phase shifter using CMOS technology is presented. The passive phase shifter is applied to the transmit/receive module from one to 16 channel in a single chip. The 35 GHz 4-element T/R module consumes less than 200 mW both transmit and receive modes. The architecture can extend to 16-channel operating at 44 GHz, thereby improving transmit power and linearity. The Ku-band 2-antenna 4-element receiver was developed using active phase shifter based on vector sum method. It is important to minimize coupling between beams because the chip contains four independent beams. The method of coupling is presented and verified.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.83-86
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• 2004

In this paper, the performance of wideband CDMA system with smart antenna is analyzed for different bandwidth(1.25MHz, 2.5MHz, 5MHz) and angular spread at base station. In detail, the spatio-temporal wideband multipath vector channel model is proposed. And the received signals in 2D-RAKE receiver are rigorously analyzed in proposed vector channel model. We consider the effect of correlation between any two elements of antenna array. Several multipahts within one chip are distinguished into each one and the strongest signal is selected as a desired one. As a result, the performance of W-CDMA system with smart antenna in spatio-temporal wideband vector channel has been improved in proportion to the increase of angular spread and bandwidth.

• ETRI Journal
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• v.38 no.3
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• pp.417-424
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• 2016

In this paper, an accurate characterization of a fabricated X-band transmit/receive module is described with the process of generating control data to correct amplitude and phase deviations in an active electronically scanned array antenna unit. In the characterization, quantization errors (from both a digitally controlled attenuator and a phase shifter) are considered using not theoretical values (due to discrete sets of amplitude and phase states) but measured values (of which implementation errors are a part). By using the presented procedure for the characterization, each initial control bit of both the attenuator and the phase shifter is closest to the required value for each array element position. In addition, each compensated control bit for the parasitic cross effect between amplitude and phase control is decided using the same procedure. Reduction of the peak sidelobe level of an array antenna is presented as an example to validate the proposed procedure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2325-2331
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• 2012

Planar square-spiral antenna using a strip conductor is proposed and analyzed for RFID system in UHF band operating from 860MHz to 960MHz. By varying the length of common line, detached distance, strip line-space, strip line-width and the number of spiral turn, the optimized antenna are designed and fabricated in compact size without a matching-stub between the input port of the proposed antenna and RFID tag chip. From the optimized results, the frequency bandwidth in VSWR<2 has covered 100MHz in the RFID UHF band. The antenna gain has obtained 3.5dBi at the center frequency of 910MHz and the desired beam pattern has shown directional pattern on elevation and azimuth angle. Therefore, the proposed antenna is suitable for practical RFID applications requiring various tag chips with the specific input impedance.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.1
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• pp.47-52
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• 2008

In this paper, the small PIFA with dual bandwidth using LTCC is the proposed. The proposed PIFA is designed and fabricated for dual resonance bands (K-PCS and WiBro). It consists of two layers. The bottom layer shape PIFA has 120MHz bandwidth (1.727 ~ 1.847 GHz), it satisfied K-PCS. The top layer shape stacked element has 110MHz bandwidth (2.302 ~ 2.412 GHz), it satisfied WiBro. The top layer is stacked on the bottom layer for electric coupling. Maximum radiation gain of K-PCS, WiBro bands are 2.11 dBi, 3.71 dBi respectively. For miniaturization of the antenna structure, the PIFA using LTCC ( ${\varepsilon}_r\;=\;8$ ) chip is fabricated. The proposed PIFA shows the effect of SAR reduction also. A defect that is fabricated by stacking up the layers in the design of PIFA is complemented by fabricated in using LTCC chip.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.3
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• pp.43-49
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• 2008

The Real Time Location System (RTLS) is very important in the ubiquitous society for real time tracking of men, high price assets, and logistics products. In this work, we developed an active RF system for RTLS and tested its performance. The RTLS system developed in this work was constructed of three active readers and one active tag. The small size tag developed in this work operated with a coin type battery. To make the tag smaller, we used an internal PCB antenna and a chip antenna. We tested the performance of the tag. To reduce the manufacturing cost of our RF system, we used low price RF transceiver CC2510 chip-set. The CC2510 chip-set provided RSSI(Received Signal Strength Indicator) signal which could be used to determine the distances between an active tag and three active readers.