• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.11
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• pp.49-56
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• 1992

In this paper a band-pass filter using dielectric resonators with tuning screw and spacer at Ku-band is designed and constructed. For the filter design and construction, the coupling coefficient K between two resonators is numberically evaluated. The external quality factor Q$_{ex}$ is also calculated with a microstrip line which is necessary for the field excitation of dielectric resonator. The coupling between dielectric resonator and microstrip line depends mainly upon the magnetic field and is principal parameter in band-pass filter. The Q$_{ex}$ and K data which are evaluated by numberical analysis are practically applied to the filter construction. The theoretical Band-pass filter responses are given by Chebyshev approximation and they are nearly similar to the experimental results.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.463-469
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• 2016

In this paper, the use of a dual composite right/left-handed coplanar waveguide (CPW) transmission line is proposed for the design of a band rejection filter. The notch property of the filter is achieved by combining the convex signal line with the shorted concave meander line, and the equivalent circuit model is extracted from the geometry of the unit cell for organizing the band rejection property. Then the equivalent parameters of the unit cell are analyzed to identify those behaviors. And the dispersion characteristics and energy distributions are simulated. In the end, the band rejection filter is manufactured by cascading two proposed unit cells. We show that the measurement result for the resonant frequency demonstrates good agreement with the simulation result and the band rejection filter provides a rejection performance of 17.5 dB at the stopband frequency ranging from 869 MHz to 894 MHz.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.215-218
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• 2009

In this paper, Dual-band bandpass filter studied design using Parallel Coupled SIR(Stepped Impedance Resonator). This Dual-band bandpass filter design SIR of half-wavelength by Parallel-coupled type that is available to RFID system and Changed structure in Meander form by size reduce. Because seen Dual-band bandpass filter is designed so that is applicable for frequency 433MHz and 2.45GHz of RFID system is very wide distance between two pass-band, establish 433MHz by fundamental frequency and controlled 2.45GHz by 2st spurious resonance frequency bandstop filter of 1st spurious resonance frequency and Parallel coupled SIR Combine to remove 1st spurious resonance frequency.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.368-374
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• 2002

In this paper, we introduce a procedure to obtain a equivalent circuit of comb-line band pass filter. By employing equivalent circuits of each asymmetrical coupled line. we composed the full equivalent circuit of comb-line bandpass filter and derived simple design equations for extracting each line's impedance. To show the validity of design equations, we simulated and fabricated a planar type comb-line bandpass filter, which has center frequency 1.8㎓, band-width 50㎒ and four resonators. The resulting filter is very compact, have broad stop band with the second pass band centered at four times the center frequency of the first pass band. The experimental results show exact performances of design specification.

• Current Optics and Photonics
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• v.2 no.6
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• pp.629-634
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• 2018

A broad dual-band terahertz metamaterial filter with sharp out-of-band rejections is designed and demonstrated. The center frequencies of the first and the second bands occur at 0.35 THz and 0.96 THz with 3 dB relative bandwidth of 31% and 17%, respectively. Results are measured using a THz time-domain spectroscopy system that shows agreement with simulations. Physical mechanisms of the broad dual-band resonance are clarified based on transmissions of different structures and surface current density distributions. Influence of structure parameters on the transmission characteristics are discussed. Symmetry of the structure ensures the filter polarization independence at normal incidence. These results supported by the design of the filter could find applications in broad multi-band sensors, terahertz communication systems, and other emerging terahertz technologies.

• Journal of electromagnetic engineering and science
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• v.16 no.1
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• pp.19-23
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• 2016

This paper presents a novel design for dual-band bandpass filters. The proposed filters are applicable to the carrier aggregation of the TV white space (TVWS) band and long-term evolution (LTE) band for cognitive radio applications. The lower passband is the TVWS band (470-698 MHz) whose fractional bandwidth is 40 %, while the higher passband is the LTE band (824-894 MHz) with 8 % fractional bandwidth. Since the two passbands are located very close to each other, a transmission zero is inserted to enhance the rejection level between the two passbands. The TVWS band filter is designed using magnetic coupling to obtain a wide bandwidth, and the LTE band filter is designed using dielectric resonators to achieve good insertion loss characteristics. In addition, in the proposed design, a transmission zero is placed with cross-coupling. The proposed dual-band bandpass filter is designed as a two-port filter (one input/one output) as well as a three-port filter (one common input/two outputs). The measured performances show good agreement with the simulated performances.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.162-167
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• 2009

In this paper, we present a compact Ultra-Wideband band-pass filter using a high-pass filter and low-pass filter. The structure of our proposed band-pass filter is very simple and the DGS(Defected Ground Structure) structure is used to get the low-pass filter characteristic. Our proposed band-pass filter can be much smaller than a cascaded filter. As a result of measurement the insertion loss is less than 0.5dB throughout the pass-band of $2.1GHz{\sim}10.56GHz$, the return loss is more than 20dB and the group delay maximum variation is 0.23ns from 0.12ns to 0.35ns.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.8
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• pp.68-73
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• 2010

In this paper, a compact Ultra-Wideband band-pass filter with notched band at 5.8GHz by using LC resonator is proposed. The structure of the proposed band-pass filter is very simple, and the DGS(Defected Ground Structure) is used to get the low-pass filter characteristics and the LC resonator is used to get the notched filter. The proposed band-pass filter can be much smaller than a cascaded filter type. The LC resonator is designed with a radial stub and small stub. As a result of measurement, the insertion loss is less than 0.5dB throughout the pass-band of 2.21GHz~10.92GHz, the return loss is more than 16dB and the maximum variation of group delay is 0.29ns and a notched band is 5.2GHz~6.2GHz.

• Journal of electromagnetic engineering and science
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• v.16 no.3
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• pp.164-168
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• 2016

A dual-band through-the-wall imaging radar receiver for a frequency-modulated continuous-wave radar system was designed and fabricated. The operating frequency bands of the receiver are S-band (2-4 GHz) and X-band (8-12 GHz). If the target is behind a wall, wall-reflected waves are rejected by a reconfigurable $G_m-C$ high-pass filter. The filter is designed using a high-order admittance synthesis method, and consists of transconductor circuits and capacitors. The cutoff frequency of the filter can be tuned by changing the reference current. The receiver system is fabricated on a printed circuit board using commercial devices. Measurements show 44.3 dB gain and 3.7 dB noise figure for the S-band input, and 58 dB gain and 3.02 dB noise figure for the X-band input. The cutoff frequency of the filter can be tuned from 0.7 MHz to 2.4 MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1259-1268
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• 2010

In this paper, we presented a new LC prototype synthesis method for the multi-band filter. For synthesis a multi-band filter with the required frequency response, we proposed the diagram of poles and zeros, also, we proposed the optimization process for finding the combination of optimized poles and zeros. From the transfer and reflection functions calculated from poles and zeros, we performed the quasi-elliptic LC prototype synthesis of multi-band filter. Using the proposed LC prototype synthesis method of multi-band filter, dual-band filter operating at GSM(880~960 MHz) and ISM(2,400~2,500 MHz) and triple-band filter operating at GSM(880~960 MHz) and ISM(2,400~2,500, 5,725~5,850 MHz) were designed and fabricated.