• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권9호
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• pp.481-487
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• 2004

The Ku band that has been using for the satellite communication and broadcasting would be changed to K/Ka bands. The satellite system requires the antenna structure to fabricate low loss and small antenna that is able to be integrated with other Rf circuits for both Rx and Tx. So we should design it with dual feed antennas at K/Ka bands, high isolation between two different feeds and broadband circular polarization. This paper proposes the LTCC(Low Temperature Co-fired Ceramic) process for integration with other Rf circuits and the Axial mode of the helical antenna to satisfy those requirements.

• 한국전기전자재료학회논문지
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• 제15권4호
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• pp.344-348
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• 2002

As microelectronics technology continues to progress, there is also a continuous demand on highly integration and miniaturization of systems. For example, it is desirable to package several integrated circuits together in multilayer structure, such as multichip modules, to achieve higher levels of compactness and higher performance. Passive components (i.e., capacitors, resistors, and inductors) are very important fort many MCM applications. In addition, the low-temperature co-fired ceramic (LTCC) process has considerable potential for embedding passive components in a small area at a low cost. In this paper, we investigate a method of statistically modeling integrated passive devices from just a small number of test structures. A set of LTCC inductors is fabricated and their scattering parameters (s-parameters) are measured for a range of frequencies from 50MHz to 5GHz. An accurate model for each test structure is obtained by using a building block based modeling methodology and circuit parameter optimization using the HSPICE circuit simulator.

• 한국전자파학회논문지
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• 제14권7호
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• pp.750-755
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• 2003

본 논문에서는 새로운 형태의 3-라인 발룬을 제안하였다. 먼저 3-라인 발룬의 등가회로를 제시하였고, 이등가회로의 각 포트에서의 전압과 전류의 관계를 이용하여 임피던스 행렬,［Z］를 구하고 이를［S］파라미터로 변환하여 제시하였다.［S］파라미터를 이용하여, 제시한 등가회로가 발룬으로 동작할 수 있도록 하는 설계식을 도출하였다 본 논문에서 제안한 등가회로와 설계식의 타당성 및 유용성을 검증하고자 2.4 GHz ISM 대역에서 동작하는 MLC(Multi-layer Ceramic) 칩 발룬을 설계하였고, LTCC(Low Temperature Co-fired Ceramic) 기술을 이용하여 제작하였다. 새로운 3-라인 발룬의 등가회로와 LTCC 기술을 이용한 다층구조를 동시에 적용함으로써 2012사이즈의 초소형 발룬을 구현할 수 있었다. 제작된 발룬의 측정 결과는 3차원 전자장 시뮬레이션 결과 와 매우 유사하였고, 넓은 대역에서 매우 우수한 위상 및 진폭 평형 특성을 보였다. 본 논문에서 제안한 3 라인 발룬은 본 논문에서 보인 것처럼 LTCC 기술을 이용하여 매우 쉽게 구현이 가능할 뿐만 아니라 인쇄회로기판 상의 마이크로 스트립라인 등을 이용하여도 구현이 가능하며 작은 사이즈의 우수한 특성을 가진 발룬이 요구되는 무선랜이나 블루투스 등의 무선 통신 시스템 등에 매우 유용하게 적용될 수 있다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1232-1233
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• 2006

To co-fire with commercial LTCC (Low Temperature Co-fired Ceramic) materials at $850^{\circ}C{\sim}880^{\circ}C$, different contents of $B_2O_3$ were added to the $Bi_2O_3-ZnO-Nb_2O_5$ (BZN) ceramics. According to the test results, the cubic phase of BZN was transformed into orthorhombic in all the test materials. $BiNbO_4$ phase was formed in test materials with $2{\sim}5wt%$ of $B_2O_3$ addition. The phase transformation of cubic BZN was controlled during the synthesis process with excess ZnO content. The Cubic and orthorhombic phases of BZN could coexist and be sintered densely at $850^{\circ}C/2hr$.

• 마이크로전자및패키징학회지
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• 제18권4호
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• pp.63-70
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• 2011

Anorthite forming glass frits in amounts up to 25 vol% of the silver powder were added to improve the adhesion between the conductor pattern formed by thick film photoimageable process and the low temperature co-fired ceramics (LTCC) substrate. The sheet resistance of the conductor pattern was raised from 0.13 ${\Omega}/{\square}$ to 2.25 ${\Omega}/{\square}$ as the volume percentage of glass frit increased up to 25 vol%. The adhesion strength was improved with this glass frit increase, but it decreased when the glass content exceeded 20 vol% which are possibly attributed to the liquid pool effect and the reduced fracture toughness in the interface between conductor and LTCC layer. The shrinkage of the width of the conductor pattern decreased with the addition of glass contents.

• 산업기술연구
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• 제25권B호
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• pp.175-182
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• 2005

This paper presents a LTCC Balun-BPF, which is a BPF(band pass filter) with a Balun in a single LTCC chip for the direct interface with a MMIC chip having balanced inputs. The physical dimension of the designed Balun-BPF is $2.4{\times}2.0{\times}0.88mm^3$ and the used dielectric constant ${\varepsilon}_r$ is 36. A Balun of three-lines structure with striplines and a BPF of comb-line structure was combined into the Balun-BPF. The simulated result shows 4.8㏈ of insertion loss, 178~179 degree of the phase imbalance, 14㏈ of the return.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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• pp.14-14
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• 2010

Recently, low temperature co-fired ceramic (LTCC) technology has gained a remarkable application potential in sensors, actuators and micro systems fields because of its very good electrical and mechanical properties, high reliability and stability as well as possibility of making 3D micro structures. In this study, we investigated the effects of annealing treatment on the electrical properties of $Pb(ZrTi)O_3$ (PZT) thin films deposited on LTCC substrate. PZT thin films were deposited on Au / LTCC substrates by RF magnetron sputtering method. Then, the change of the crystallization of the films were investigated under various annealing temperatures and times. The results showed that the crystallization of the films were enhanced as increasing annealing temperatures. The film, annealed at $700^{\circ}C$, 3min, was well crystallized in the perovskite structure.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2005년도 하계학술대회
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• pp.133-136
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• 2005

This paper presents a LTCC Balun-BPF, which is a BPF(bandpass filter) with a Balun in a single LTCC chip for the direct interface with a MIC chip having balanced inputs. The physical dimension of the designed Balun-BPE is $2.4{\times}2.0{\times}0.88m^3$ and the used dielectric constant ${\varepsilon}_r$ is 36. A Balun of three-lines structure with striplines and a BPF of comb-line structure was combined into the Balun-BPF. The simulated result shows 4.8dB of insertion loss, $178{\sim}179$ degree of the phase imbalance, 14dB of the return

• Journal of electromagnetic engineering and science
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• 제10권3호
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• pp.92-98
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• 2010

A new wideband bandstop filter(BSF) with a sharp roll-off characteristic is introduced in a stripline structure in this paper. The BSF consists of two sections: the first is two capacitively coupled $\lambda/4$ short-circuited lines with opposite ground positions, while the second is a capacitively coupled $\lambda/4$ short-circuited line. The BSF provides three transmission zeros within the stopband and better than 22 dB rejection over the whole wireless local area network (WLAN) band from 5.15 to 5.825 GHz. The BSF, cascaded to an U.S. ultra-wideband(UWB: 3.1~10.6 GHz) band-pass filter(BPF), is simulated with HFSS and realized with low-temperature co-fired ceramic(LTCC) green tape with a dielectric constant of 7.8. The measurement results agree well with the HFSS simulation results. The size of the UWB BPF including the BSF is $3{\times}6.3\times0.45\;mm^3$.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.506-510
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• 2003

In this paper, a meander-line chip antenna with stacked layer is suggested, designed and fabricated employing the LTCC(Low Temperature Co-fired Ceramic) fabrication techniques. To reduce the antenna chip size, the meander-line antenna strip is distributed over three layer. Layers one interconnected using via holes. A 2.4 GHz chip antenna with size of $3.75{\times}7.9{\times}1.0 mm^3$ is designed and fabricated using the LTCC technique. Measurements of the fabricated antenna show 160 MHz bandwidth and 3.75 dBi maximum gain. The Measured reflection coefficient and radiation patterns agree well with the prediction by electromagnetic simulation.