• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.748-754
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• 2000

A novel single feed wide band CP stacked microstrip antenna using crossed slots has been designed, fabricated and measured. For the single rediating element the designed 10dB return loss bandwidth is 34.5%99.45~13.54 GHz), 3dB axial ratio bandwidth is 18.7%(11.17~13.39GHz), and 6 dB gain bandwidth is 29%(10.21~13.64GHz). For the 2$\times$2 array designed using a sequential rotation method, the 10dB return loss bandwidth is 35.9%(9.69~13.94GHz), 3dB axial ratio bandwidth is 34.6GHz (9.93~14.03GHz), and 6dB gain bandwidth is 27.4%(10.35~13.6GHz). For the fabricated 8$\times$8 array antenna, the 10dB return loss bandwidth is 27.3%(10.17~13.41GHz), 3dB axial ratio bandwidth is 27.9GHz(10.1~13.4GHz), and the radiation pattern is good agreement with theory. This antenna can be used for broadband applications for communications or broadcasting in Ku band.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.127-134
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• 2022

A modified folded monopole slot antenna for 3G WCDMA (1.91 ~ 2.17 GHz), 4G LTE (2.17 ~ 2.67 GHz), 3.5 GHz 5G (3.42 ~ 3.7 GHz) and Wi-Fi dual band (2.4 ~ 2.484 GHz / 5.15 ~ 5.825 GHz) was proposed for the first time. The proposed antenna is designed and fabricated on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of 35 × 60 mm². The measured impedance bandwidth of the proposed antenna is 2910 MHz(1.84 ~ 4.75 GHz) and 930 MHz(5.11 ~ 6.04 GHz), antenna gain in each frequency band is from 1.811 to 3.450 dBi. In particular, it was possible to obtain a commercially suitable omni-directional radiation pattern in all frequency bands of interest.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.441-448
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• 2012

This paper proposes a multiband Multi-Input Multi-output(MIMO) antenna for universal serial bus(USB) dongle application. The proposed MIMO antenna consists of a modified meander strip line and inverted L stub. The two radiating elements of the MIMO antenna are symmetrically placed with respect to the center of the ground plane. The fabricated antenna satisfied a VSWR below 3 and an efficiency over 35 % in the LTE band 13, 17(704 MHz-787 MHz), DCS/PCS/WCDMA band(1.71 GHz-2.17 GHz), and LTE band 7(2.5 GHz-2.7 GHz). The envelope correlation coefficient(ECC) has below 0.45 in the LTE band 13, 17 and 0.1 in the DCS/PCS/WCDMA band and LTE band 7, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.727-736
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• 2002

In this paper, the broadband microstrip antenna with small size, thin-profile, conformability and ease of manufacture is proposed for providing PCS(down link: 1.75GHz∼1.78GHz, up link: 1.84GHz∼1.87GHz) '||'&'||' IMT-2000(down link: 1.92GHz∼1.98GHz, up link: 2.11GHz∼2.17GHz) services simultaneously. By using double U-slots and matching stub, the bandwidth and operating performance of printed antenna was significantly improved, with need for a complex fabrication procedure. We have also studied the various parameters of the U-slot$_2$for the performances of the antenna. Impedance bandwidth of the wideband microstrip antenna with the double U-slots is about 30.45% (VSWR<2)

• Journal of Advanced Navigation Technology
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• v.6 no.1
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• pp.52-62
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• 2002

Electrical characteristics of two types of 20 GHz Push-Push GaAs MESFET dielectric resonator oscillators having Wilkinson and T-junction power combiners for the output stage have been investigated. The Push-Push oscillator for suppressing fundamental frequency 10 GHz and enhancing 20 GHz has been designed and realized in microstrip configuration on 20 mil thick RT-Duroid(${\varepsilon}_r$=2.52) teflon substrate. Two different types of power combiners, T-junction and Wilkinson, have been considered. Whenever one type of the combiners has been adopted for the output circuit, output power, phase noise and fundamental frequency suppression characteristics of the oscillator have been measured. When the Wilkinson power combiner was used, a maximum output power of 5.67 dBm, a phase noise of -105.5 dBc/Hz at an offset frequency of 100 kHz and a fundamental frequency suppression of -29.33 dBc have been measured. When the T-junction power combiner was used, a maximum output power of -1.17 dBm, a phase noise of -102.2 dBc/Hz at an offset frequency of 100 kHz and a fundamental frequency suppression of -17.84 dBc have been measured.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.257-262
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• 2017

In this paper, we proposed a rectangular planar monopole antenna with a double sleeve that applied to a half-cut and a discontinuous feed structure. A rectangular planar monopole antenna with a double sleeve was cut in half along the magnetic symmetry line, and impedance matching was achieved by a discontinuous structure was applied to a feeder and by adjusting the double sleeve gap. We used the HFSS simulator of ANSYS company to confirm the antenna parameter property, and the antenna size was $21{\times}40mm^2$. In the proposed antenna, the simulation frequency range with VSWR of 2 or less was 2.6GHz to 10.25GHz. The bandwidth was 7.65GHz. The frequency range of the fabricated antenna was 3.3GHz to 9.75GHz, and the bandwidth was 6.45GHz. The measured radiation pattern frequencies were 3.5GHz, 5.5GHz, 7.5GHz, and 9.5GHz. A radiation pattern similar to the dipole antenna pattern was obtained at all frequencies.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.3
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• pp.411-424
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• 2017

An all-digital delay-locked loop (DLL) for a mobile memory interface, which runs at 0.11-2.5 GHz with a phase-shift capability of $180^{\circ}$, has two internal DLLs: a global DLL which uses a time-to-digital converter to assist fast locking, and shuts down after locking to save power; and a local DLL which uses a phase detector with an adaptive phase sampling window (WPD) to reduce jitter accumulation. The WPD in the local DLL adjusts the width of its sampling window adaptively to control the loop bandwidth, thus reducing jitter induced by UP/DN dithering, input clock jitter, and supply/ground noise. Implemented in a 65 nm CMOS process, the DLL operates over 0.11-2.5 GHz. It locks within 6 clock cycles at 0.11 GHz, and within 17 clock cycles at 2.5 GHz. At 2.5 GHz, the integrated jitter is $954fs_{rms}$, and the long-term jitter is $2.33ps_{rms}/23.10ps_{pp}$. The ratio of the RMS jitter at the output to that at the input is about 1.17 at 2.5 GHz, when the sampling window of the WPD is being adjusted adaptively. The DLL consumes 1.77 mW/GHz and occupies $0.075mm^2$.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.7
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• pp.65-70
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• 2012

In this paper, a compact UWB (Ultra Wideband) BPF(Band-Pass Filter) with dual notched bands is proposed using a hybrid Composited Right-Left Handed (CRLH) and Defected Ground Structure (DGS). To avoid the interferences such as Wireless LAN (Center frequency: 2.4GHz and 5.8GHz), the CRLH is employed to obtain the dual notched bands and the DGS is used to obtain the wide stop-band above the pass-band. The fabricated filter has good performance and has more than 30dB rejection at the center frequency of 2.4 GHz and 5.8GHz. The dual notched bands are easily movable by changing the CRLH parameter. Also the insertion loss is less than 0.4dB in the lower pass-band and 0.7dB in the upper pass-band, and it has small group delay variation less than 0.6ns. The size of the fabricated filter is very compact (17mm*17mm).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.4
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• pp.379-385
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• 2002

In this paper, frequency trifler fur 8 GHz local oscillator was designed and fabricated using MESFET. The third order harmonic was generated by biasing the transistor on A class. The fundamental frequency and the second harmonic were suppressed by using λ$\_$g//2 stub and band pass filter. As results, conversion gain of 2.67 ㏈ at 8.31 GHz, the harmonic suppression of -41.17 ㏈c, the bandwidth of 510 ㎒ were measured.red.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5827-5831
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• 2011

In this paper, 5Ghz microstrip patch antenna for wireless LAN is designed, fabricated, and measured. To obtain wide bandwidth and high gain, antenna parameters such as patch size(W, L), the length of the slot(C), and the slot width(D) are simulated by HFSS(High Frequency Structure Simulator). From these parameters optimized, the microstrip patch antenna is fabricated using FR-4 substrate. The measured results of the antenna are as follows: The center frequency of 5.2 GHz, insertion loss of -41.17dB, bandwidth of 258MHz, and VWSR of 1.1.