• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.9
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• pp.1027-1034
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• 2014

We present the Low Power Broadband Low noise amplifier(LNA) that can be applied a whole bandwidth from 3G to 4G LTE. This multi input LNA was designed to steadily amplify through a multi input method regardless the size of the input signal and operate on a wide range of frequency band from a standard 3G CDMA band 1.2GHz to LTE band 2.5GHz. The designed LNA consumes an average of 6mA on a 1.2V power supply and this was affirmed using computer simulation tests. The amplification which was corresponded to the lowest input signal is at a maximum of 20dB and was able to obtain the minimum value of the gain of -10dB. The Noise figure is less than 3dB at a High-gain mode and is less than 15dB at a Low-gain mode.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.5
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• pp.100-105
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• 2010

A multi-band low noise amplifier (LNA) is designed in 90 nm RF CMOS process for 3GPP LTE (3rd Generation Partner Project Long Term Evolution) applications. The designed multi-band LNA covers the eight frequency bands between 1.85 and 2.8 GHz. A tunable input matching circuit is realized by adopting a switched capacitor array at the LNA input stage for providing optimum performances across the wide operating band. Current steering technique is adopted for the gain control in three steps. The performances of the LNA are verified through post-layout simulations (PLS). The LNA consumes 17 mA at 1.2 V supply voltage. It shows a power gain of 26 at the normal gain mode, and provides much lower gains of 0 and -6.7 in the bypass-I and -II modes, respectively. It achieves a noise figure of 1.78 dB and a IIP3 of -12.8 dBm over the entire band.

• Journal of The Korean Astronomical Society
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• v.45 no.2
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• pp.39-48
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• 2012

We investigate non-LTE effects on the $H_3^+$ level populations to help the analysis of the observed 2 and 3.5 micron $H_3^+$ emissions from the Jovian ionosphere. We begin by constructing a simple three-level model, in order to compute the intensity ratio of the R(3,4) line in the hot band to the Q(1,0) line in the fundamental band, which have been observed in the Jovian auroral regions. We find that non-LTE effects produce only small changes in the intensity ratios for ambient $H_2$ densities less than or equal to $5{\times}10^{11}cm^{-3}$. We then construct two comprehensive models by including all the collisional and radiative transitions between pairs of more than a thousand known $H_3^+$ rovibrational levels with energies less than 10000 $cm^{-1}$. By employing these models, we find that the intensity ratios of the lines in the hot and fundamental bands are affected greatly by non-LTE effects, but the details depend sensitively on the number of collisional and radiative transitions included in the models. Non-LTE effects on the rovibrational population become evident at about the same ambient $H_2$ densities in the comprehensive models as in the three-level model. However, the models show that rotational temperatures derived from the intensities of rotational lines in the ${\nu}_2$ and $2{\nu}_2$ bands may differ significantly from the ambie temperatures in the non-LTE regime. We find that significant non-LTE effects appear near and above the $H_3^+$ peak, and that the kinetic temperatures in the Jovian thermospheric temperatures derived from the observed line ratios in the 2 and 3.5 micron $H_3^+$ emissions are highly model dependent.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.76-78
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• 2011

In this paper, 0.8 GHz and 1.8 GHz dual-band antenna was designed for global system for mobile communications (GSM) and the Long Term Evolution (LTE) The proposed antenna was made using CST Microwave Studio 2009. My script antenna's substrate is Taconic TLY-5 and dielectric constant is 2,2 and has 1.0mm thickness with a compact design of the proposed antenna, Thus it shows that this proposed antenna can be used in Wireless Communication System.

• Journal of IKEEE
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• v.23 no.3
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• pp.917-924
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• 2019

This paper presents a wideband low noise amplifier (LNA) that is suitable for LTE-Advanced and 5G communication standards employing carrier aggregation (CA). The proposed LNA encompasses a common input stage and a dual output second stage with a buffer at each distinct output. This architecture is targeted to operate in both intra-band (contiguous and non-contiguous) and inter-band CA. In the proposed design, the input and second stages employ a gm enhancement with resistive feedback technique to achieve self-biasing, enhanced gain, wide bandwidth as well as reduced noise figure of the proposed LNA. An up/down power controller controls the single input single out (SISO) and single input multiple outputs (SIMO) modes of operation for inter-band and intra-band operations. The proposed LNA is designed with a 45nm CMOS technology. For SISO mode of operation, the LNA operates from 0.52GHz to 4.29GHz with a maximum power gain of 17.77dB, 2.88dB minimum noise figure and input (output) matching performance better than -10dB. For SIMO mode of operation, the proposed LNA operates from 0.52GHz to 4.44GHz with a maximum voltage gain of 18.30dB, a minimum noise figure of 2.82dB with equally good matching performance. An $IIP_3$ value of -6.7dBm is achieved in both SISO and SIMO operations. with a maximum current of 42mA consumed (LNA+buffer in SIMO operation) from a 1.2V supply.

• Journal of IKEEE
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• v.24 no.1
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• pp.90-96
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• 2020

As various communication services have emerged due to the development of mobile communication technology, there is a need for a wideband antenna supporting multiple communication services with one antenna. In this paper, we propose a planar slot wideband antenna that can support all the communication services of 3.1~4.99GHz, the low frequency band of 5G, in addition to the existing communication services such as WiFi, LTE 2300/2500, and WiMAX. Through the simulation, the optimized antenna design parameters were obtained, and the antenna was fabricated to implement an antenna with a frequency bandwidth of 1.96~6.01GHz (S11 <-10dB) and presented the radiation pattern and gain of the antenna. The proposed antenna is a multi-band antenna that can provide all the services of LTE, Wifi, WiMAX, and 5G low frequency bands. It can be used as a repeater antenna in radio shadow area such as buildings, dense areas, and ships.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7309-7316
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• 2014

In this paper, a triple-band multiplexer using a microstrip transmission line was designed and fabricated to make use of a low power portable base station. This multiplexer was used in the triple-band including the cellular, WCDMA and LTE mobile frequency band, and designed to have an insertion loss of 0.8 dB, low SWR of 1.5 in the passband and a band rejection of 15 dB in the stopband. From the measured results obtained by a confidence test for the fabricated multiplexer samples, the maximum insertion loss and SWR of the fabricated multiplexer samples in all passbands of 824-894MHz, 1920-2170 MHz and 2500-2600 MHz were below 0.71 dB and 1.38, and the attenuations in the stopbands were better than 15 dB. Therefore, the triple-band multiplexer has good performance and satisfies the design specifications.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.522-528
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• 2017

In this paper, we propose a multi-band antenna for wearable devices using metal frame coupling. The proposed antenna has a $45mm{\times}35mm$ antenna using metal frame and a ground dual coupling structure. The proposed multi-band antenna in this paper is optimized for small devices such as wearable devices. By using the metal frame as a part of the antenna, the volume of the antenna is reduced and satisfies under VSWR 3:1 impedance bandwidth of 70 MHz (870 ~ 940 MHz) in low frequency band, 280 MHz (1600 ~ 1880 MHz) and 280 MHz (1900 ~ 2170 MHz) in high frequency band. It also verified the applicability of wearable devices by measuring wireless performance indicators such as TRP/TIS.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.3
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• pp.248-256
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• 2015

In this paper, a hybrid MIMO antenna for the metal phone with auxiliary slot for 4th generation mobile communication is designed and implemented. Auxiliary slot locates on the rear metal cover of the phone, and handles for LTE class 40 band. The auxiliary slot operates hybrid with a monopole antenna. Studied antenna satisfies under VSWR 3:1 for LTE class 13/ LTE class 14/ CDMA/ GSM/ DCS/ PCS/ W-CDMA/ LTE class 40 bands. ECC(Envelope Correlation Coefficient) value for MIMO characteristic is less than 0.2 over the whole design bands. Average gains and antenna efficiencies measured by MTG anechoic chamber were -5.57~-1.45 dBi and 27.75~71.6 %, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.4
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• pp.395-398
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• 2016

In this paper, a hybrid MIMO antenna for the mobile communication metal phone with auxiliary letter slot is designed and implemented. Auxiliary letter slot locates on the rear metal cover of the phone, and operates on LTE class 40 band. The slots of two letters are designed and operated with monopole+IFA hybrid antenna. Antenna satisfies under VSWR 3: 1 for LTE class 13 / LTE class 14 / CDMA / GSM / DCS / PCS / W-CDMA / LTE class 40 bands. Average gains and antenna efficiencies measured by the anechoic chamber were -5.57~-1.45 dBi and 27.75~71.6 %, respectively.