• Journal of Korea Multimedia Society
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• v.6 no.1
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• pp.161-166
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• 2003

This paper presents a high gain LNA for a bluetooth application using 0.25$\mu\textrm{m}$ CMOS technology. The conventional one stage LNA has a low power gain. The presented one stage LNA using a cascode inverter LNA with a voltage reference and without a choke inductor has an improved Power gain. Simulation results of the 2.4GHz designed LNA shows a high power gain of 21dB, a noise figure of 2.2dB, and the power consumption of 255mW at 2.5V power supply.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.75-82
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• 2003

이동체 탑재형 안테나는 설치 장소의 특성상 소형화와 경량화가 필수적인 요소이다. 그러므로 이동체 탑재형 안테나의 경우 반사판형 안테나보다 마이크로스트립 어레이 안테나가 널리 쓰이고 있다. 본 고에서는 마이크로 스트립 슬롯 어레이 안테나를 설계하였다. 만족스러운 고 이득을 얻을 수 있으며 동시에 패치 소자의 개수를 줄이기 위해 패치 단일 소자가 가급적 고 이득을 낼 수 있는 구조로 설계하였다. 본 고에서 설계한 슬롯 안테나는 기생슬롯을 가진 H 자형 타입의 소자이다. 설계는 제작상의 오차를 고려하여, 운용 주파수 11.7~12.75 GHz에서 VSWR 1.8:1 이하를 목표로 하였다. 제작된 안테나의 측정결과는 11.7~12.75 GHz대역에 걸쳐 VSWR < 1.8의 만족한 결과를 보이고, 단일 소자의 시뮬레이션 이득 결과는 10 dBi를 보였으며 $4\times4$ 어레이를 했을 경우 이득은 22 dBi의 값을 보였다. 제작되어진 안테나는 추후 급전 네트웍의 최적화를 통해 상호 간섭(Mutual Coupling)을 최소화하여 효율을 최대화한다면 직접 위성 서비스를 수신하기 위한 초소형 안테나로 활용될 수 있을 것으로 기대된다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.6
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• pp.473-478
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• 2021

This paper designed a wideband, high gain planar trapezoidal monopole antenna using backside frequency selective surface (FSS) according to the need for wideband and high gain antenna required in various fields such as rapidly increasing wireless communication, autonomous vehicles, 5G wireless communication and wideband applications. The proposed antenna uses a dual metallic to have a structural difference from the existing FSS. By solving the complexity of the design antenna using genetic algorithms (GA) and high frequency structural simulators (HFSS) simulations, the proposed antenna is not only produce a high efficiency but also presents a wide bandwidth of 3.52 to 5.92 GHz and a gain of 10.5 dBi over the entire bandwidth, with the highest gain of 11.8 dBi at 5.1 GHz. It has been confirmed that the gain increased 8.6 dBi as the 36% impedance bandwidth of 1.8 GHz compared to the existing antenna improved to the 50% impedance bandwidth of 2.4 GHz.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.341-348
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• 2018

A WLAN dual band dipole antenna with parasitic elements and a reflector is presented for high gain operation. The parasitic elements are used for practical application and high gain operation of the radiation pattern at the WLAN dual band. The proposed antenna consists of three layers, and has dimensions of $74mm{\times}40 mm{\times}31.4mm$. From the experimental results, the achieved impedance bandwidths were 1035 MHz (2.031-3.066 GHz) and 1119 MHz (5.008-6.127 GHz), respectively. The measured maximum gain at each WLAN band was 6.69 dBi and 7.81 dBi, respectively.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.83-88
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• 2017

In this paper, we propose a three-element CRPA array with improved low-elevation gain. The proposed antenna consists of a feed patch and a radiating patch, and the feed patch is connected by a coaxial cable. The radiating patch is electromagnetically coupled to the feed patch, which allows to improve the low-elevation gain of the antenna. To demonstrate the suitability of the proposed antenna, the antenna characteristics are measured in a full anechoic chamber. The resulting bore-sight gain is 2.8 dBic with an axial ratio of 2.7 dB, and the average gain at the low-elevation direction of $75^{\circ}$ is -1.4 dBic. The results verify that the proposed antenna is suitable for CRPA arrays with anti-jamming capability.

• The KIPS Transactions:PartA
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• v.12A no.6 s.96
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• pp.531-538
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• 2005

In the high performance Analog Information Processing Systems(AIPS), gain boosting or additional gain stage is required when the gain is not sufficient with one stage amplification. This work shows that high gain is neatly obtained by enhancing the gain using the negative resistance element. Compared to the conventional techniques, the proposed scheme enjoys full output swing, small circuit area and power consumption, and the applications to various configurations of amplifiers. The negative resistance element is placed between the differential output nodes when used in the Op-Amp. The HSPICE simulation indicates that enhancement of more than 40 dB is readily obtained in this simple configuration when the negative resistance element is implemented in the form of cross-coupled CMOS inverters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.1
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• pp.68-79
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• 1992

In the high speed analog system satellite communication system, video signal processing and optical fiber interface circuits, GaAs high gain operational amplifier is advantageous due to obtain a high gain because of its low transconductance and other drawbacks, such as low frequency dispersion and process variation. Therefore in this paper, a circuit techniques for improving the voltage gain for GaAs MESFET amplifier is presented. Also, various types of existing current mirror and current mirror proposed are compared.To obtain the high differential gain, bootstrap gain enhancement technique is used and common mode feedback is employed in differential amplifier.The simulation results show that gain is higher than that of basic amplifier about 18.6dB, and stability and frequency performance of differential amplifier are much improved.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.177-180
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• 1998

높은 Q가 요구되는 고주파 신호 처리용 필터 설계에서는 흔히 SC 필터를 사용하고 있다. 처리하고자 하는 신호가 고주파수이고, 선택도 Q 값이 매우 높은 경우에는, SC 필터에 사용하는 증폭기의 성능이 빠르고, 직류 성분 이득이 커야만 한다. 이와 같은 속도와 이득이 요구됨에 따라 일반적인 범용 증폭기는 이득이 충분치 못하여 사용이 제한되고, 설사 범용 증폭기를 이용하여 필터를 구성하였다 해도 그 특성에 많은 제한을 줄 수밖에 없다. 또한 GaAS MESFET op amp의 경우, 최근의 논문에서도 60[dB] 이상의 이득이 제안된 바 없으므로, 필터 구성시 또 다른 설계 기술이 요구된다. 따라서 본 논문에서는 GaAS MESFET 능동 SC 적분기의 유한한 이득과 offset 전압을 보정한 새로운 구조의 적분기를 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.8
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• pp.867-880
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• 1992

In this paper, a circuit design techniques for Improving the voltage gain of the GaAs MESFET single amplifier is presented. Also, various types of existing current mirror and proposed current mirror of new configuration are compared. To obtain the high differential mode gain and low common mode gain, bootstrap gain enhancement technique Is used and common mode feedback Is employed In the design of differential amplifier. The simulation results show that designed differential amplifier has differential gain of 57.66dB, unity gain frequency of 23.25GHz. Also, differential amplifier using common mode feedback with alternative negative current mirror has CMRR of 83.S8dB, stew rate of 3500 V /\ulcorners.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.647-653
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• 2005

According to the design concept of microwave front-end, a low noise amplifier block using HBT cascode topology is proposed to provide high gain and low noise figure with low bias current. We has implemented MMIC-LNA with a modified configuration using inductors to show low noise at the emitter and base of cascoded HBT-MMIC amplifier. The measured performance of the designed MMIC-LNA at 3.7GHz are a gain of 19dB, noise figure of 2.7dB and image rejection of 35dBc using a supply of 3mA and 2.7V. We can convinced that cascoded amplifier block to fulfill a high gain, low noise and image rejection if microwave front-end receiver is designed by cascode MMEC-LNA with the active image rejection filter.