• Journal of electromagnetic engineering and science
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• v.14 no.2
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• pp.47-53
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• 2014

This paper presents a high gain and high harmonic rejection low-noise amplifier (LNA) for software-defined radio receiver. This LNA exploits the high quality factor (Q) series resonance technique. High Q series resonance can amplify the in-band signal voltage and attenuate the out-band signals. This is achieved by a source impedance transformation. This technique does not consume power and can easily support multiband operation. The chip is fabricated in a $0.13-{\mu}m$ CMOS. It supports four bands (640, 710, 830, and 1,070MHz). The measured forward gain ($S_{21}$) is between 12.1 and 17.4 dB and the noise figure is between 2.7 and 3.3 dB. The IIP3 measures between -5.7 and -10.8 dBm, and the third harmonic rejection ratios are more than 30 dB. The LNA consumes 9.6 mW from a 1.2-V supply.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.441-444
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• 2007

In this paper, the resonance characteristics of ZnO-based film bulk acoustic resonator (FBAR) devices with high-quality multi-layer reflectors are proposed. The ultrathin Cr film $(300\;\AA-thick)$ between $SiO_2$ film and W film is formed by a sputtering-deposition in order to enhance the adherence at their interfaces. The resonance frequency was observed to vary with the number of the reflectors. This seems to be attributed to the change in the effective thickness of the ZnO film. Also, increasing the number of layers has led to a significant improvement of the series/parallel quality factor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.204-207
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• 2007

Film bulk acoustic wave resonator (FBAR) technology has attracted a great attention as a promising technology to fabricate the next-generation RF filters mainly because the FBAR technology can be integrated with current Si processing. The RF filters are basically composed of several FBAR devices connected in parallel and in series, and their characteristics depend highly on the FBAR device characteristics. Thus, it is important to design high quality FBAR devices by device or process optimization. This kind of effort may enhance the FBAR device characteristics, eventually leading to FBAR filters of high performance. In this paper, we describe the methods to more effectively improve the resonance characteristics of the FBAR devices.

• Journal of electromagnetic engineering and science
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• v.16 no.3
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• pp.143-149
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• 2016

This work presents a method used for designing a broadband class-E power amplifier that combines the two techniques of a nonlinear shunt capacitance and a low quality factor of a series resonator. The nonlinear shunt capacitance theory accurately extracts the value of class-E components. In addition, the quality factor of the series resonator was considered to obtain a wide bandwidth for the power amplifiers. The purpose of using this method was to produce a simple topology and a high efficiency, which are two outstanding features of a class-E power amplifier. The experimental results show that a design was created using from a 130 to 180 MHz frequency with a bandwidth of 32% and a peak measured power added efficiency of 84.8%. This prototype uses an MRF282SR1 MOSFET transistor at a 3-W output power level. Furthermore, a summary of the experimental results compared with other high-efficiency articles is provided to validate the advantages of this method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2090-2094
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• 2007

Film bulk acoustic wave resonator(FBAR) technology has attracted a great attention as a promising technology to fabricate the next-generation RF filters mainly because the FBAR technology can be integrated with current Si processing. The RF filters are basically composed of several FBAR devices connected in parallel and in series, and their characteristics depend highly on the FBAR device characteristics. Thus, it is important to design high quality FBAR devices by device or process optimization. This kind of effort may enhance the FBAR device characteristics, eventually leading to FBAR filters of high performance. In this paper, we describe the methods to more effectively improve the resonance characteristics of the FBAR devices.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.683-693
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• 2011

In this paper, a design of high current and broad-band microwave bias-tee was presented for a stable bias of a high power amplifier. An input impedance of bias-tee should be shown to 50 ohm with the wideband in order to be stably-biased the amplifier. For this design of the bias-tee, a capacitor of bias-tee for a DC block was designed with a high wide-band admittance by a parallel sum of capacitors, and a inductor for a RF choke and a DC feeding was designed with a high wide-band impedance by a series sum of inductors. As this inductor and capacitor for the sum has each SRF, band-limitation of lumped element was driven from SRF. This limitation was overcome by control of a resonance's quality factor with adding a resistor. 1608 SMD chips for design's element was mounted on the this pattern for the designed bias-tee. The fabricated bias-tee presented 10 dB of return loss and wide-band about 50 ohm input impedance at 10 MHz~10 GHz.