• ETRI Journal
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• v.43 no.1
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• pp.133-140
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• 2021

Herein, we present a compact transversal bandpass filter (BPF) with an extremely wide upper stopband and multiple transmission zeros (TZ). Three signal transmission paths with shorted stubs and open-coupled lines allow signal transmission from input port to output port. Two resonant modes can be excited simultaneously and managed easily for bandpass response. Eleven TZs are achieved via transmission path cancelation; an extremely wide upper stopband with an attenuation level better than -12 dB is achieved up to 11.7 f0, where f0 is the center frequency (CF). In addition, bandwidth and CF can be controlled by adjusting electrical lengths. For proof of concept, a wideband BPF centered at 1.04 GHz with 3 dB fractional bandwidths of 49.2% was designed, fabricated, and evaluated. The overall circuit measures 0.045λg × 0.117λg; good agreement was observed between the measured and simulated results.

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.582-588
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• 2012

In this paper, a highly miniaturized and performed UWB bandpass filter has been newly designed and implemented by embedding all the passive elements into a multi-layered PCB substrate with high dielectric $SrTiO_3$ composite film for 3.1 - 4.75 GHz compact UWB system applications. The high dielectric composite film was utilized to increase the capacitance densities and quality factors of capacitors embedded into the PCB. In order to reduce the size of the filter and avoid parasitic EM coupling between the embedded filter circuit elements, it was designed by using a $3^{rd}$ order Chebyshev circuit topology and a capacitive coupled transformation technology. Independent transmission zeros were also applied for improving the attenuation of the filter at the desired stopbands. The measured insertion and return losses in the passband were better than 1.68 and 12 dB, with a minimum value of 0.78 dB. The transmission zeros of the measured response were occurred at 2.2 and 5.15 GHz resulting in excellent suppressions of 31 and 20 dB at WLAN bands of 2.4 and 5.15 GHz, respectively. The size of the fabricated bandpass filter was $2.9{\times}2.8{\times}0.55(H)mm^3$.

• ETRI Journal
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• v.41 no.1
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• pp.117-123
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• 2019

This paper presents a tri-wideband bandpass filter (TWB-BPF) with compact size, high band-to-band isolation, and multiple transmission zeros (TZs). The proposed TWB-BPF is based on a multiple-mode resonator (MMR), which is interpreted by the method of the even- and odd-mode analysis technique. The MMR can excite 11 resonant modes, where the first two modes comprise the first passband, the next four modes form the second passband, and the last five modes are used to generate the third passband. In addition, 10 TZs are yielded to obtain high band-to-band isolation and wide stopband suppression characteristics up to $14.95f_{c1}$ ($f_{c1}$ is the center frequency of the first passband). To verify the proposed filter, a TWB-BPF with 3-dB fractional bandwidths (FBWs) of 37.4%, 43.5%, and 40.4% is designed, fabricated, and measured.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.1
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• pp.39-44
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• 2008

In this paper, fully embedded 2.4GHz WLAN band pass filter (BPF) was investigated into a multi-layered organic packaging substrate using high Q spiral stacked inductors and high Dk MIM capacitors for low cost RF System on Package (SOP) applications. The proposed 2.4GHz WLAN BPF was designed by modifying chebyshev second order filter circuit topology. It was comprised of two parallel LC resonators for obtaining two transmission zeros. It was designed by using 2D circuit and 3D EM simulators for finding out optimal geometries and verifying their applicability. It exhibited an insertion loss of max -1.7dB and return loss of min -l7dB. The two transmission zeros were observed at 1.85 and 6.7GHz, respectively. In the low frequency band of $1.8GHz{\sim}1.9GHz$, the stop band suppression of min -23dB was achieved. In the high frequency band of $4.1GHz{\sim}5.4GHz$, the stop band suppression of min -l8dB was obtained. It was the first embedded and the smallest one of the filters formed into the organic packaging substrate. It has a size of $2.2{\times}1.8{\times}0.77mm^3$.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.4 no.1
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• pp.31-36
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• 2005

In this paper, a planar type bandpass filter in multilayered PCB is presented. The multilayered PCB structure has some advantages on fabricating microwave devices such as the size reduction and ability of tight coupling by folding or embedding. The proposed BPF has two transmission zeros at the both sides of the center frequency by using independent electric and magnetic coupling structure. The designed BPF with four layer teflon PCBs of dielectric constant 2.94 has dimensions of 24x20x1.524 in mm, center frequency of 2.47GHz and bandwidth of about l00MHz. A good agrement is achieved between the measured result and the simulated one. The influences of air gaps between the layers are also analyzed and presented.

• KIISE Transactions on Computing Practices
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• v.20 no.11
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• pp.610-614
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• 2014

Like many types of scientific data, results from simulations of volcanic ash diffusion are of a clustered sparse matrix in the netCDF format. Since these data sets are large in size, they generate high storage and transmission costs. In this paper, we suggest a new method that reduces the size of the data of volcanic ash diffusion simulations by converting the multi-dimensional index to a single dimension and keeping only the starting point and length of the consecutive zeros. This method presents performance that is almost as good as that of ZIP format compression, but does not destroy the netCDF structure. The suggested method is expected to allow for storage space to be efficiently used by reducing both the data size and the network transmission time.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.475-485
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• 2010

This paper proposes a novel concept for a microstrip resonator that can function as a filter and as an antenna at the same time. The proposed structure consists of an outer ring, an open loop-type inner ring, a circular patch, and three ports. The frequencies where the proposed structure works as a filter and as an antenna, respectively, are determined primarily by the radius of the inner ring and the circular patch. The measured results show that, when the microstrip resonator operates as a filtering device, this filter has about 15.1 % bandwidth at the center frequency of 0.63 GHz and a minimum insertion loss of 1.5 dB within passband. There are three transmission zeros at 0.52 GHz, 1.14 GHz, and 2.22 GHz. In the upper stopband, cross coupling - taking place at the stub of the outer ring - and the open loop-type inner ring produce one transmission zero each. The circular patch generates the dual-mode property of the filter and another transmission zero, whose location can be easily adjusted by altering the size of the circular patch. The proposed structure works as an antenna at 2.7 GHz, showing a gain of 3.8 dBi. Compared to a conventional patch antenna, the proposed structure has a similar antenna gain. At the resonant frequencies of the filter and the antenna, high isolation(less than -25 dB) between the filter port and the antenna port can be obtained.