• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1105-1111
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• 2006

In this paper, using low-temperature co-fired ceramic(LTCC) based system-in-package(SiP) technology, a very compact power amplifier LTCC module was designed, fabricated, and then characterized for 60 GHz wireless transmitter applications. In order to reduce the interconnection loss between a LTCC board and power amplifier monolithic microwave integrated circuits(MMIC), bond-wire transitions were optimized and high-isolated module structure was proposed to integrate the power amplifier MMIC into LTCC board. In the case of wire-bonding transition, a matching circuit was designed on the LTCC substrate and interconnection space between wires was optimized in terms of their angle. In addition, the wire-bonding structure of coplanar waveguide type was used to reduce radiation of EM-fields due to interconnection discontinuity. For high-isolated module structure, DC bias lines were fully embedded into the LTCC substrate and shielded with vias. Using 5-layer LTCC dielectrics, the power amplifier LTCC module was fabricated and its size is $4.6{\times}4.9{\times}0.5mm^3$. The fabricated module shows the gain of 10 dB and the output power of 11 dBm at P1dB compression point from 60 to 65 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.11
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• pp.1176-1183
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• 2003

In this paper, miniature voltage-controlled oscillator(VCO) for 1.6 ㎓ PCS band is designed and implemented using the LTCC technique. Circuit level design using commercial components is performed, and passive L, C elements embedded in LTCC substrate is optimized by simulation tools. Embedded passive components are modeled into equivalent circuits and their circuit parameters are extracted for circuit simulation. Utilizing the designed embedded passive elements and 21 layers LTCC substrate, VCO with 4.0${\times}$4.0${\times}$1.6 ㎣ dimensions is designed and fabricated. Developed VCO operates in 2.7 V with 8.5 ㎃ current consumption. The phase noise performance of VCO is below -112.61 ㏈c/㎐ at 100 ㎑ offset and harmonic suppression characteristics is measured above -30 ㏈.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.1
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• pp.71-76
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• 2004

A compact embedded tapped-line combline filter with interdigital capacitors using low temperature co-fired ceramic (LTCC) technology for wireless application is proposed. Also, in-situ measurement using T-pattern microstrip resonator was performed to acquire exact knowledge of electrical properties of the LTCC substrate. The proposed filter makes it possible to realize a relatively small size, 2.7mm${\times}$2.03mm. by employing interdigital and combline structure. It shows 1.8 ㏈ insertion loss, 37.6㏈ return loss, and 280 MHz bandwidth at the center frequency of 5.09 GHz. Its small size and simple structure make it a good candidate as an integrated filter for various LTCC substrates.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.14-19
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• 2003

In this paper, a λ/4 hair-pin resonator is proposed to reduce the size of resonators. A LTCC MLC bandpass filter is designed using the λ/4 hair-pin resonators. The electromagnetic coupling structure between two planar resonators is analysed. The equivalent circuit is derived to explain the behavior of the LTCC MLC bandpass filter using λ/4 hair-pin resonators. A design procedure is also described. The simulated and measured results of 1.8 GHz band 2-pole bandpass filter are presented.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.31-38
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• 2003

In the current electronic technology atmosphere, MEMS (Microelectromechanical System) technology is regarded as one of promising device manufacturing technologies to realize market-demanding device properties. In the packaging of MEMS devices, the packaged structure must maintain hermeticity to protect the devices from a hostile atmosphere during their operations. For such MEMS device vacuum packaging, we introduce the LTCC (Low temperature Cofired Ceramic) packaging technology, in which embedded passive components such as resistors, capacitors and inductors can be realized inside the package. The technology has also the advantages of the shortened length of inner and surface traces, reduced signal delay time due to the multilayer structure and cost reduction by more simplified packaging processes owing to the realization of embedded passives which in turn enhances the electrical performance and increases the reliability of the packages. In this paper, the leakage rate of the LTCC package having several interfaces was measured and the possibility of LTCC technology application to MEMS devices vacuum packaging was investigated and it was verified that improved hermetic sealing can be achieved for various model structures having different types of interfaces (leak rate: stacked via; $4.1{\pm}1.11{\times}10^{-12}$/ Torrl/sec, LTCC/AgPd/solder/Cu-tube; $3.4{\pm}0.33{\times}10^{-12}$/ Torrl/sec). In real application of the LTCC technology, the technology can be successfully applied to the vacuum packaging of the Infrared Sensor Array and the images of light-up lamp through the sensor way in LTCC package structure was presented.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.3
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• pp.25-35
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• 1999

LTCC (Low Temperature Cofired Ceramic) or LTCC-M (Low Temperature Cofired ceramic on Metal) technology is one of MCM-C (Multichip Module on Ceramic) technologies and becomes to be widely used in consumer, RF and automotive electronics. As green sheets for LTCC are cofired below $1000^{\circ}C$ in comparison with those for HTCC (High Temperature Cofired Ceramic), high conductivity metal traces such as gold, silver and copper can be used. The dimensional stability in LTCC-M technology enables embedded passives to be integrated inside modules, which enhances the electrical performance and increases the reliability of the modules. Coefficient of thermal expansion and dielectric constant can be controlled by changing composition and heating profile for cofiring. In this technical review, LTCC and LTCC-M technologies are introduced and advantages of those technologies are explained.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.570-572
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• 2012

In this paper, a three-dimensional (3-D) low-loss and wide-band BPF based on low-temperature co-fired ceramic (LTCC) has been presented for mm-wave wireless communication applications. The proposed BPF is designed in a 6-layer LTCC substrate. The double patch resonators are fully integrated into the LTCC dielectrics and vertical via and planar CPW transitions are designed for interconnection between embedded resonators and in/output ports and MMICs, respectively. The designed BPF was fabricated in a 6-layer LTCC dielectric. The fabricated BPF shows a centre frequency (fc) of 53.23 GHz and a 3dB bandwidth of 14.01 % from 49.5 to 56.9 GHz (7.46 GHz). An insertion loss of -1.56 dB at fc and return losses below -10 dB are achieved. Its whole size is $4.7{\times}1.7{\times}0.684mm^3$.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.11
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• pp.680-686
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• 2004

An integrated inductor using the low temperature cofiring ceramics(LTCC) technology was fabricated. The inductor has Ag circular spiral coil with 16 turns (2-turn x 8-layer) and has a dimension of 11.52mm diameter and 0.71mm thick. For the fabricated inductor, calculation method of inductance was given and it is confirmed that the calculated value is very close to the measured one. Finally as an application of the LTCC integrated inductor to low power electronic circuits, a LTCC buck DC/DC converter with 1.32W output power and 1MHz switching frequency using the inductor fabricated was developed. For the converter the maximum efficiency of about 81% was obtained.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.39-43
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• 2003

Thermal management is very important for the success of high density circuit design in LTCC. In this paper, LTCC substrates containing thermal via and pad were fabricated in order to study the influence of the thermal dissipation. To realize the accurate thermal analysis for structure design, a series of simple thermal conductivity measurement by laser flash method and parametric numerical analysis have been carried out. The LTCC substrate including via and Ag pad has good thermal conductivity over 103 W/mK which is 44% value of pure Ag material. Thermal behaviors with via arrays, size and density in the LTCC substrate were studied by numerical method.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.1
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• pp.47-52
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• 2008

In this paper, the small PIFA with dual bandwidth using LTCC is the proposed. The proposed PIFA is designed and fabricated for dual resonance bands (K-PCS and WiBro). It consists of two layers. The bottom layer shape PIFA has 120MHz bandwidth (1.727 ~ 1.847 GHz), it satisfied K-PCS. The top layer shape stacked element has 110MHz bandwidth (2.302 ~ 2.412 GHz), it satisfied WiBro. The top layer is stacked on the bottom layer for electric coupling. Maximum radiation gain of K-PCS, WiBro bands are 2.11 dBi, 3.71 dBi respectively. For miniaturization of the antenna structure, the PIFA using LTCC ( ${\varepsilon}_r\;=\;8$ ) chip is fabricated. The proposed PIFA shows the effect of SAR reduction also. A defect that is fabricated by stacking up the layers in the design of PIFA is complemented by fabricated in using LTCC chip.