• Journal of the Korean Ceramic Society
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• v.35 no.7
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• pp.699-705
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• 1998

This paper is about design of optimal structure of microstrip dielectric ceramic antenna with rectangular electrode patches in accordance with the cavity model and fabrication of its prototype sample operating at the frequency of 900 MHz. Results of this work can be employed as a useful too to develop and diversify ceramic antenna having superior performance and omni-directivity to that of current helical antenna.

• Journal of electromagnetic engineering and science
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• v.4 no.3
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• pp.107-112
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• 2004

In this paper, the phase noise of 900 MHz VCO is improved using modified strip line square ring resonator. In order to demonstrate the phase noise improvement of the proposed VCO, the same circuit was manufactured using shorted-circuit resonator. In condition of the same bias current, the phase noise of the proposed VCO with modified square ring resonator is suppressed by 7 dB as - 103 dBc/Hz at 100 kHz offset compared to the conventional VCO with short-circuit resonator. From the proposed VCO, we achieved output power of - 4.8 dBm, harmonics suppression of 16 dB, and tuning bandwidth of 100 MHz. The proposed VCO consumed 5 mA at 3 V, and its size is 1.2 cm ${\times}$ 1.0 cm.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.104-107
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• 2000

We designed and implemented the RFIC(RF front-end IC) for DTV(Digital TV) tuner. The DTV tuner RF front-end consists of low noise IF amplifier fur the amplification of 900 MHz RF signal and down conversion mixer for the RF signal to 44MHz IF conversion. The RFIC is implemented on ETRI 0.8u high resistive (2㎘ -cm) and evaluated by on wafer, packaged chip test. The gain and IIP3 of IF amplifier are 15㏈ and -6.6㏈m respectively. For the down conversion mixer gain and IIP3 are 13㏈ and -6.5㏈m. Operating voltage of the IF amplifier and the down mixer is 5V, current consumption are 13㎃ and 26㎃ respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.183-186
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• 1999

A 900 71Hz RF band-pass amplifier for wireless communication systems is designed and fabricated. HSPICE simulation results show that the amplifier can achieve a tunable center frequency between 880 MHz and 920 MHz. The gain of designed amplifier is 19 dB at Q=88, and the power dissipation is about 61 mW under 3 V power supply by using the spiral inductor with negative-7m circuit and center frequency tunning circuit. The designed band-pass amplifier is implemented by using 0.6 um 2-poly-3-metal standard CMOS process.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.349-349
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• 2006

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.538-538
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• 2006

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.176-182
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• 2006

In this paper, we have measured the power of the electro-magnetic waves in the cabin of automobiles with automatic transmission or manual transmission. Measured frequency ranges are $815\~865MHz\;and\;900\~950MHz$. Experimental studies are conducted by measuring the radiated power of the frequency spectrum for above frequency bands. The $\lambda/2$ dipoles used for measurement are fabricated to comply with the COMMISSION DIRECTIVE 95/54/EC. Experimental results confirm that the level of radiated power in the cabin of automobile with automatic transmission is higher than that with manual transmission. The measured values are less than -85dBm for the manual transmission vehicles, but more than -79dBm for the automatic transmission vehicles.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.225-230
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• 2005

The proposed Triple-band Compact Chip Antenna using Coupled Meander line and stacked meander Structure for Mobile RFID/PCS/WiBro. The proposed antenna is designed to operate at 900, 1800, and 2350 MHz, and is realized by parasitic coupled and stacked a meander line. Meander lines are using extend length of effective current path more than monopole and contribute miniaturization. The coupled meander line controls the excitations of the Mobile RFID and PCS, stacked meander line controls the excitation of the WiBro. The proposed antenna size is $11mm\times22.5mm\times1mm$. The antenna supports 900MHz, 1800MHz and 2350MHz operations simultaneously with bandwidths of 33MHz, 230MHz and 100MHz, respectively. The proposed antenna gains are result of simulation to be -0.8dBi, 3dBi and 3.8dBi, respectively.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.2
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• pp.345-354
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• 2024

In this paper, we propose a triple band WLAN antenna for Wi-Fi 6E band with DGS. The proposed antenna has the characteristics required frequency band and bandwidth by considering the interconnection of two strip lines and three areas on the ground place. The total substrate size is 31 mm (W) × 50 mm (L), thickness (h) 1.6 mm, and the dielectric constant is 4.4, which is made of 22 mm (W₆ + W₄ + W₅) × 43mm (L₁ + L₂ + L₃ + L₅) antenna size on the FR-4 substrate. From the fabrication and measurement results, bandwidths of 340 MHz (1.465 to 1.805 GHz) for 900 MHz band, 480 MHz (2.155 to 2.635 GHz) for 2.4 GHz band and 1950 MHz (4.975 to 6.925 GHz) for 5.0/6.0 GHz band were obtained on the basis of -10 dB. Also, gain and radiation pattern characteristics are measured and shown in the frequency triple band as required.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5C
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• pp.540-547
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• 2006

This paper proposes a novel anti-collision method for the ISO/IEC 18000-6 type B protocol which is the standard protocol of the 900 MHz RFID system. We improve the anti-collision performance by reducing the transmission number of commands and the length of bits required for multi-tag identification in the ISO/IEC 18000-6 type B protocol. Simulation results show that the proposed method improves the multi-tag identification time by 21.7% over the conventional method, irrespective of number of tags.