• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.958-966
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• 2012

This paper presents a compact bluetooth/WiFi dual-mode dual-band RF front-end module(FEM) is realized by low temperature co-fired ceramic(LTCC) technology. The proposed RF front-end module consists of a diplexer, baluns in the LTCC substrate, and an SPDT switch, an SP3T switch on the LTCC substrate. In order to reduce the module size and increase integration level, the proposed diplexer and balun are designed using LC lumped elements. The parasitic elements caused by coupling effect between metal pattern layers and ground plane layer are considered during the design. The fabricated dual-mode RF front-end module has 13 pattern layers including three inner ground layers and it occupies less than $3.0mm{\times}3.7mm{\times}0.66mm$.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.11
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• pp.61-68
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• 2008

In this paper, we propose a RF front-end developments for vehicle UWB radar systems. UWB systems have a very narrow pulse width that is below 1ns. Therefore, UWB is designed to have broadband quality of low power several GHz and must coexist with the radio communication system. UWB's advantages include high channel capacity and data rate, because precise resolution for multi-path can easily position estimate and Rake receiver. Also, UWB has low interference because it displays broadband quality of low power. Positioning is made possible by short range accuracy, which can reduce the expense of system design. An RF front-end module is designed using the DCR(Direct ConveRsion) method and is composed in RF for vehicles at a low-cost.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.776-779
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• 2004

A RF front-end module is designed for GIS(Gas Insulated Substation) which is employed for effective and efficient very high voltage transmission. Major advantage of the unit is improved PO detection sensitivity through minimizing the effect of surrounding interference signals, which is achieved by controlling the gain and the selection of the frequency band, for the precise detection of any UHF PO (Partial Discharge) disturbance occurred in the GIS due to some unwanted problems. For the development of the module, various switches for providing selected signal paths, wideband LNA, 3 BPF for selecting detection frequency band, and video detector are designed, fabricated and measured on 1 mm FR4 substrate with various RF components. The detection sensitivity of the unit was <-60 dBm that is sufficient to detect UHF PO signals as low as 1 pC. It is believed that the value is enough to detect the signal occurred in GIS.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.362-370
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• 2010

In this paper, a compact RF Front-end module for Wireless Fidelity(Wi-Fi) and Worldwide Interoperability for Microwave Access(WiMAX) applications is realized by low temperature co-fired ceramic(LTCC) technology. The RF Front-end module is composed of three LTCC band-pass filters, a Film Bulk Acoustic Resonator(FBAR) filter, fully embedded matching circuits, an SPDT switch for mode selection, an SPDT switch for Tx/Rx selection, and an SP4T switch for band selection. The parasitic elements of 0.2~0.3 pF are generated by the structure of stacking in the top pad pattern for DC block capacitor of SPDT switch for mode selection. These kinds of parasitic elements break the matching characteristic, and thus, the overall electrical performance of the module is degraded. In order to compensate it, we insert a parallel lumped-element inductor on capacitor pad pattern for DC block, so that we obtain the optimized performance of the RF Front-end module. The fabricated RF front-end module has 12 layers including three inner grounds and it occupies less than $6.0mm{\times}6.0mm{\times}0.728mm$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.967-975
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• 2006

In this paper, design and implementation of a very compact and cost effective front-end module are presented for IEEE 802.16 FWA(fixed Wireless Access) in the 40 GHz band. A multi-layer LTCC(Low Temperature Co-fred Ceramic) technology with cavity process to achieve excellent electrical performances is used to fabricate the front-end module. The wirebond matching circuit design of switch input/output port and waveguide transition to connect antenna are optimally designed to keep transmission loss low. To reduce the size of the front-end module, the dielectric waveguide filter is developed instead of the metal waveguide filter. The LTCC is composed of 6 layers(with the thickness of a layer of 100 um) having a relative dielectric constant of 7.1. The front-end module is implemented in a volume of $30{\times}7{\times}0.8mm^3$ and shows an overall insertion loss < 5.3 dB, and image rejection value > 49 dB.

• Journal of information and communication convergence engineering
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• v.18 no.4
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• pp.254-259
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• 2020

Phased-array antennas comprise a demanding antenna design methodology for commercial wireless communication systems or military radar systems. In addition to these two important applications, the phased-array antennas can be used in beamforming for wireless charging. In this study, a four-way analog beamforming front-end module (FEM) for a hybrid beamforming system is developed for 2.4 GHz operation. In a hybrid beamforming scheme, an analog beamforming FEM in which the phase and amplitude of RF signal can be adjusted between the RF chain and phased-array antenna is required. With the beamforming and beam steering capability of the phased-array antennas, wireless RF power can be transmitted with high directivity to a designated receiver for wireless charging. The four-way analog beamforming FEM has a 32 dB gain dynamic range and a phase shifting range greater than 360°. The maximum output RF power of the four-way analog beamforming FEM is 40 dBm (=10 W) when combined the four individual RF paths are combined.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.154-161
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• 2011

This paper presents a compact integrated transceiver module for 2.4 GHz band applications using Low Temperature Co-fired Ceramic(LTCC) technology. The implemented transceiver module is divided into an RF Front-End Module (FEM) part and a transceiver IC chip part. The RF FEM part except an SPDT switch and DC block capacitors is fully embedded in the LTCC substrate. The fabricated RF FEM has 8 pattern layers and it occupies less than $3.3\;mm{\times}5.2\;mm{\times}0.4\;mm$. The measured results of the implemented RF FEM are in good agreement with the simulated results. The transceiver IC chip part consists of signal line, power line and transceiver IC for 2.4 GHz band communication system. The fabricated transceiver module has 9 layers including three inner grounds and it occupies less than $12\;mm{\times}8.0\;mm{\times}1.1\;mm$. The implemented transceiver module provides an output power of 18.1 dBm and a sensitivity of -85 dBm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1287-1293
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• 2008

Antenna switch module(ASM) for quad-band was developed. This module was integrated by RFIPD(RF integrated passive device) and transistor switch instead of LTCC-type device using low pass filters, diodes and passive elements in RF front end module for cellular phone. This module leads to low cost and miniaturization(The area is $5{\times}5\;mm$ and the thickness is 0.8 mm). The insertion loss and the return loss of each band were averagely measured as 1.0 dB(insertion loss), 15.1 dB(GSM/EGSM return loss) and 19 dB(DCS/PCS return loss), respectively.

• Information and Communications Magazine
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• v.28 no.11
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• pp.16-23
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• 2011

휴대폰은 스마트화되면서 퍼스널 컴퓨터에 버금가는 성능으로 발전하고 있다. 또한 모바일 환경에서 높은 데이터 전송 속도 및 많은 사용자가 동시에 사용할 수 있는 시스템을 적용하고 있다. 차세대 이동통신서비스나 B4G(Beyond 4 Generation)에서는 다중밴드/다중 모드/다중경로 처리구조의 융합 단말기가 시장을 형성하게 되며, 갈수록 휴대폰의 RF Front-End는 복잡하게 된다. 또한 FEM(Front End Module)의 성능은 단말기 시스템의 품질(QoS, Quality of Services)을 좌우하는 핵심부품으로 High Data Rate를 위하여 고성능화가 요구되고 있다. 본고에서는 FEM의 발전 트랜드와 구성하는 블록도 및 주요 핵심부품의 특성과 모듈의 소형화 패키징 기술에 관하여 제시하였다. 또한 4G LTE와 Wimax듀얼밴드 Tx/Rx통합 FEM을 소개하였고, 향후에 구성되게 되는 Future FEM의 블록도를 제시하였다.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.4
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• pp.258-264
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• 2015

The first 77 GHz transceiver that applies a heterodyne structure-based linear frequency modulation-frequency shift keying (LFM-FSK) front-end module (FEM) is presented. An LFM-FSK waveform generator is proposed for the transceiver design to avoid ghost target detection in a multi-target environment. This FEM consists of three parts: a frequency synthesizer, a 77 GHz up/down converter, and a baseband block. The purpose of the FEM is to make an appropriate beat frequency, which will be the key to solving problems in the digital signal processor (DSP). This paper mainly focuses on the most challenging tasks, including generating and conveying the correct transmission waveform in the 77 GHz frequency band to the DSP. A synthesizer test confirmed that the developed module for the signal generator of the LFM-FSK can produce an adequate transmission signal. Additionally, a loop back test confirmed that the output frequency of this module works well. This development will contribute to future progress in integrating a radar module for multi-target detection. By using the LFM-FSK waveform method, this radar transceiver is expected to provide multi-target detection, in contrast to the existing method.