• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.904-911
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• 2011

This paper deals with transmission characteristics of a new dual resonant structure for designing waveguide band-pass filter. The structure which has a pass-band between two adjacent stop-bands in a single body consists of circular ridged aperture and four armed conducting patch. The dual resonant behavior of the structure can be represented by a combination of LC series and parallel resonant circuits. Also these resonant properties can be easily controlled by varying the geometry of the aperture and four armed conducting patch. Actually, the structure is fabricated on the microstrip substrate by use of etching technique so that it is formed an iris type resonator which can be easily put into the transverse plane of the waveguide. We use WR-90 standard waveguide, adapters, and VNA(vector network analyzer) to measure the resonant characteristics of the structure. It is very useful to design and to improve the cutoff skirts characteristics in the waveguide band-pass filter design area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.191-196
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• 2016

Applying diffraction of waves and muffler principle, the theory of macroscopic air ventilation with soundproofing was explained. Soundproofing frequency range can be selected by this method. The sound wave was attenuated at the resonator located between double-layered walls. A soundproof plate was designed and the experiment was processed. There are two air holes of diameter of 5cm and thickness of 8cm on the surfaces per each soundproofing cell. There was a transmission loss of about 25dB and it is more than at least 10dB compared with that of the Comnex technology of wave cancellation by air holes in Japan. Furthermore, there was no soundproof frequency selection in the Comnex technology.

• Korean Journal of Optics and Photonics
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• v.6 no.3
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• pp.245-256
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• 1995

Rugate filters of inhomogeneous refractive index were designed using the Fourier transform and the effect of reflectance, stop bandwidth, optical thickness, and Q function on the rugate filter was investigated. An iterative correction process using a merit function was employed to fit an initial design to the target spectrum. Three Q functions derived by Sossi, Bovard, and Fabricius, respectively, were compared in terms of the number of iteration, merit function, and optimum optical thickness. The result shows that after a number of iterations the Q functions by Bovard and Fabricius produce high rejection rugate filters closer to the target spectrum than the Sossi's Q function and the optimal optical thickness is determined by the stop-band width of the rugate filter. ilter.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.181-182
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• 2009

In the machinery, the brake system is as important part as machine's working. If the machine doesn't stopped, would be big occident. For the ships, it is important too. Use the windlass winch to stop the voyage and use mooring winch to keep the stop in the port. In this study, improve the braking power divided the brake band and search the optimize portion.

• Journal of the Optical Society of Korea
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• v.16 no.4
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• pp.343-348
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• 2012

This paper described an off-axis five-mirror-anastigmatic telescope. It is composed of three aspheric surfaces and one spherical surface while the third mirror and fifth mirror have the same parameters at the same place. This configuration is useful for having wide field of view. The strip full field of view for the near infrared telescope is $20^{\circ}{\times}0.2^{\circ}$. The entrance pupil is located in front of the first mirror. There is an intermediate image between the second mirror and the third mirror. The entrance pupil diameter is 100 mm and the effective focal length is 250 mm. The spectral range is $0.85-1.75{\mu}m$. The pixel pitch is $15{\mu}m$. The image quality is near the diffraction limit. Some methods were used to restrain the stray light such as a field stop near the intermediate image, the baffle, the narrow-band pass filter and a stop in front of the focal plane.

• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.570-574
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• 2008

The 'gate non-stop system utilizing RFID (900MHz)', which is the core of this research, is the system which connects RFID to recognize the vehicle information without stopping when a vehicle (trailer) passes a gate to carry in or out containers in a terminal and automatically provides the container information provided by the terminal for the RFLDU device installed in the vehicle.In order to design and implement this, the RFID technical section uses a UHF band (900MHz) RFID tag and a reader and implements a RFID middleware and an application program for smooth data collection and execution (operation). In addition, the system stability was verified through experiments and operations of the system implemented in this research at real harbors/quays, and based on the verified result, the maximization of vehicle (trailer) and terminal productivity and the reduction of distribution cost are expected.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.1
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• pp.27-32
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• 2015

In this paper, a mushroom typed electromagnetic band gap (EBG) structure to be inserted in the printed circuit board (PCB) inner layer in order to stabilize the PCB power line is proposed for global-navigation satellite service (GNSS). In designing the proposed EBG structure, the target stop-bandwidth was designed from 1.55GHz to 1.81GHz including GNSS and mobile communication-related frequency bandwidth. In this bandwidth, the insertion loss(S21) was observed below about -40dB. From the simulation results, it is expected that the stabilization of power delivery network (PDN) structure in the PCB circuit design should be improved and the effective correspondence to EMI will be helpful.

• Journal of Advanced Navigation Technology
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• v.5 no.2
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• pp.141-148
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• 2001

This paper describe the development of narrow-band passband filter with small package and low loss, high selectivity performance. This filter is placed between power amplifier and frequency mixer of IMT-2000 mobile equipment. The elliptic-function narrow-band passband filter is designed with new architecture using the microstrip line. This package is very small by $3.2cm{\times}1.25cm$ and have the 3 % 3 dB bandwidth. Also in the passband the insertion loss is about 2.5 dB and is better than older RF SAW filter(insertion loss: 3.2 dB). In the stop-band it has the two deep notch under the -56 dB.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.103-109
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• 2008

In this papaer, a new type of ${\lambda}_g/4$ short stub band pass filter and ${\lambda}_g/2$ open stub band pass filter are purposed. Both are designed using FSCS technique for harmonic suppression. The proposed filters that used FSCS technique and a broadband stop filter is integrated to band pass filter to suppress the harmonics. The BSF are also placed between stubs so that the size is larger than prevent as compared to conventional one. The propose filters have center frequency of 5.8 GHz, bandwidth of 50% and harmonics suppressin is 120% has in bandwith. The measurement results in the case of ${\lambda}_g/4$ short stub filter, insertion loss of 0.5 dB, return loss of 14 dB are achieved and in the case of ${\lambda}_g/2$ open stub filter, loss of 0.8 dB, return loss of 14.4 dB are achieved. The simulation results and the measurement results are almost the same.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.300-305
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• 2012

In this paper, a miniaturized bow-tie monopole UWB antenna with band rejection characteristic is proposed. To miniaturize the proposed antenna, a perfect magnetic wall(PMW) condition is applied to primitive bow-tie monopole antenna. An uneven ground patch, a tapered feeding structure and a edge-chopped main patch are adapted for impedance matching. A quater-lambda slot resonator is inserted at main patch to prevent interference in UWB band from another band. The proposed antenna is fabricated on Taconic RF60-A substrate with relative permittivity of 6.15. The size of the proposed antenna is $30.0{\times}39.7mm^2$, which is only 45 % of the conventional bow-tie monopole antenna. The proposed antenna covers full UWB band with return losses less than -10 dB and has band stop characteristic in 5 GHz WLAN band. The maximum gains are within -1.0~5.0 dBi, the group delay variations are within 1.0 ns and the radiation patterns show directivity characteristics in x-y plane.