• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.5 no.2
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• pp.61-67
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• 2012

In this paper, In this paper, we consider a dynamic range in the frequency converter to obtain a high conversion gain and linearity while operating area proposed to broaden the design. Super-heterodyne RF Front-End style was applied to the active mixer stage, GaAs devices were used. Circuit design easy and simple forms benefit circuit is constructed in the drain mixer, passive mixer with the operating area were compared and analyzed. The simulation results of the conversion gain of 2.4dB and 0.2dBm about a gain-compression point, and showed the dynamic range of 71.9dB, when compared with passive mixers, dynamic range of approximately 6dB improvement was identified. Measurements of an approximately 2dB conversion gain and-1.0dBm of the gain-compression point, and confirmed that the active area of 71.1dB. When compared with passive mixers, dynamic range of is reduced by approximately 8dB has been improved.

• Journal of electromagnetic engineering and science
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• v.14 no.2
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• pp.61-67
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• 2014

This paper presents a zero-IF CMOS RF receiver, which supports three channel bandwidths of 5/10/40MHz for LTE-Advanced systems. The receiver operates at IMT-band of 2,500 to 2,690MHz. The simulated noise figure of the overall receiver is 1.6 dB at 7MHz (7.5 dB at 7.5 kHz). The receiver is composed of two parts: an RF front-end and a baseband circuit. In the RF front-end, a RF input signal is amplified by a low noise amplifier and $G_m$ with configurable gain steps (41/35/29/23 dB) with optimized noise and linearity performances for a wide dynamic range. The proposed baseband circuit provides a -1 dB cutoff frequency of up to 40MHz using a proposed wideband OP-amp, which has a phase margin of $77^{\circ}$ and an unit-gain bandwidth of 2.04 GHz. The proposed zero-IF CMOS RF receiver has been implemented in $0.13-{\mu}m$ CMOS technology and consumes 116 (for high gain mode)/106 (for low gain mode) mA from a 1.2 V supply voltage. The measurement of a fabricated chip for a 10-MHz 3G LTE input signal with 16-QAM shows more than 8.3 dB of minimum signal-to-noise ratio, while receiving the input channel power from -88 to -12 dBm.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1565_1566
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• 2009

This paper presents the design and analysis of RF Front End for Wireless Heartbeat measurement System. In this work LNA, an inductor connected at the gate of the cascode transistor and capacitive cross-coupling are strategically combined to reduce the noise and the nonlinearity influences of the cascode transistors in a differential LNA. The Mixer is implemented by using the Gilbert-type configuration, cross pmos injection technique and the resonating technique for the tail capacitance. The resulting LNA achieves 1.26dB NF, better than 1.88dB NF Typical. Also Mixer resulting achieves 9.8dB at 100KHz.

• 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.22 no.12
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• pp.1078-1085
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• 2011

In this paper, we analyze the relationship between energy per bit and the data rate with the variation of the system bandwidth. A existing power model is mathematical model to express power consumption of each device. In this paper, we have to investigate the system level energy model for the RF front-end of a wireless transceiver. Also, the effects of the signal bandwidth, PAR, date rate, modulation level, transmission distance, specific attenuation of frequency band, and the signal center frequency on the RF front-end energy consumption and system capacity are considered. Eventually, we analyze the relationship between energy per bit and the data rate with the variation of the system bandwidth so that we simulate the minimum energy per bit in the several Gbps data rate using Shannon capacity theory.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.175-184
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• 2006

In this paper, we describe a 900MHz CMOS RF transceiver using an ISM band for ZigBee applications. The architecture of the designed rx front-end, which consists of a low noise amplifier, a down-mixer, a programmable gain amplifier and a band pass filter. And the tx front-end, which consists of a band pass filter, a programmable gain amplifier, an up-mixer and a drive amplifier. A low-if topology is adapted for transceiver architecture, and the total current consumption is reduced by using a low power topology. Entire transceiver is verified by means of post-layout simulation and is implemented in 0.18um RF CMOS technology. The fabricated chip demonstrate the measured results of -92dBm minimum rx input level and 0dBm maximum tx output level. Entire power consumption is 32mW(@1.8VDD). Die area is $2.3mm{\times}2.5mm$ including ESD protection diode pads.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.4
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• pp.489-499
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• 2011

RFID technologies, which allow collecting, storing, processing, and tracking information by wirelessly recognizing the inherent ID of object through an attached electronic tag, have a variety of application areas. This paper presents a novel carrier leakage suppression RF(CLS-RF) front-end for ultra-high-frequency RF identification reader. The proposed reader CLS-RF front-end structure generates the carrier leakage replica through the nonlinear path that contains limiter. The limiting function only preserves the frequency and phase information of the leakage signal and rejects the amplitude modulated tag signal in the envelope. The carrier leakage replica is then injected into the linear path that contains phase shifter. Therefore, the carrier leakage signal is effectively cancelled out, while not affecting the gain of the desired tag backscattering signal. We experimentally confirm that the prototype shows a significant improvement in the leakage to signal ratio by up to 36 dB in 910 MHz, which is consistent with our simulation results.

• Journal of IKEEE
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• v.14 no.4
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• pp.257-262
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• 2010

We design a CMOS front-end with wide variable gain and low power consumption for 5.25 GHz band. To obtain wide variable gain range, a p-type metal-oxide-semiconductor field-effect transistor (PMOS FET) in the low noise amplifier (LNA) section is connected in parallel. For a mixer, single balanced and folded structure is employed for low power consumption. Using this structure, the bias currents of the transconductance and switching stages in the mixer can be separated without using current bleeding path. The proposed front-end has a maximum gain of 33.2 dB with a variable gain range of 17 dB. The noise figure and third-order input intercept point (IIP3) are 4.8 dB and -8.5 dBm, respectively. For this operation, the proposed front-end consumes 7.1 mW at high gain mode, and 2.6 mW at low gain mode. The simulation results are performed using Cadence RF spectre with the Taiwan Semiconductor Manufacturing Company (TSMC) $0.18\;{\mu}m$ CMOS technology.)

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.205-208
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• 2002

This paper presents a quantitative analysis on the intermodulation product between transmitter W-CDMA leakage signal and receiver out of band blocker, and proposes design guide lines for overcoming the effect in receiver design. Our analysis shows that duplexer isolation, attenuation and LNA IIP3 are mainly responsible for the 3rd order intermodulation product. Analysis also shows that LNA IIP3 required for meeting 3GPP TS 34.121 specification is about 1 ㏈m with duplexer isolation of 50 ㏈ and duplexer attenuation of 24㏈.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.122-127
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• 2016

In this paper, new spectrum sensing schemes based on analog/RF front-end processing are introduced for IoT wireless sensor networks. While the conventional approaches for wireless channel cognition have been issued in signal processing area, the RF spectrum cognition concept makes it feasible to achieve cognitive wireless sensor networks (C-WSNs). The spectrum cognition at RF processing is categorized as four kinds of sensing mechanisms. Two recent reseaches are described as promising candidates for the C-WSN. One senses spectrum by the frequency discriminating receiver, the other senses and detects from the frequency selective super-regenerative receiver. The introduced systems with simple and low-power RF architectures play dual roles of channel sensing and demodulation. simultaneously. Therefore, introduced spectrum sensing receivers can be one of the best candidates for IoT wireless sensor devices in C-WSN environments.