• Title/Summary/Keyword: Band-Stop

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Design and Experiment of Waveguide Limiter with Band-Pass Characteristics Using PIN Diode (PIN 다이오드를 이용한 대역 통과 여파 특성을 갖는 리미터 설계 및 실험)

  • Park, Jun-Seo;Kim, Byung-Mun;Cho, Young-Ki
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.9
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    • pp.1065-1072
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    • 2012
  • In this paper, the method of design of the waveguide band-pass filter and limiter in radar system is proposed. First, we design a self-resonant iris, which can behave as a band-pass filter by mounting the PIN diode on the iris. When low power microwave is incident on the proposed element, the element behaves as a band-pass filter. Under a high power microwave condition, however, the element behaves as a limiter having wide band stop characteristics. The fabricated element has a pass band with -0.7 dB insertion loss at 10 GHz under the low power condition and isolation about 25 dB under the high power condition.

Dual-Band Stop Filter Using Metamaterial TLs (Metamaterial 전송선을 이용한 이중 대역 저지 필터)

  • Oh, Hee-Seok;Nam, Sang-Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.2
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    • pp.124-128
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    • 2009
  • This raper proposes a dual-bandstop filter, which is based on a metamaterial transmission line using the composite right/left-handed (CRLH) and dual composite right/left-handed (D-CRLH) structures. The metamaterial structure is used for miniaturization and dual-bandstop operation at the TDMB frequency range (195 MHz) and DVB-T/H frequency range (670 MHz). The size of the proposed filter is $30{\times}15\;mm$, and the -10 dB bandstop fractional bandwidth is approximately 73 % and 50 % at each frequency, respectively.

Permittivity Characteristic Analysis of Planar Substrates Using H-shaped Resonant Aperture (H-모양 공진 개구를 이용한 평면 기판의 유전율 특성 분석)

  • Yeo, Junho;Lee, Jong-Ig
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2018.05a
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    • pp.55-56
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    • 2018
  • In this paper, a method for analyzing the dielectric constant of a planar substrate is proposed. To this end, a band-stop filter was created by adding a H-shaped resonant aperture to the ground plane of a microstrip transmission line. A planar substrate of 2 mm thickness was placed behind the ground plane of the microstrip transmission line and the change of the resonant frequency with the change of the dielectric constant of the substrate was investigated. It can be seen that the change ratio of the frequency to the reference resonant frequency is larger than that of the conventional complementary split ring resonator structure.

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A Transversal Low Pass Filter Using Charge Coupled Device with Two Level Aluminum Electrode Structure (2중 알루미늄 전극구조의 Charge Coupled Device를 이용한 저역 여파기)

  • 신윤승;김오현
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.18 no.3
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    • pp.25-34
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    • 1981
  • Aluminum anodization method has been investigated for fabricating charge coupled device(CCD) with two-level aluminum gate structure. Al2O3 films were formed to a thickness of 400-500A, by anodizing aluminum with 30-35V of anode voltage for 2 hours using 2 % ammonium tartrate solution as an electrolyte. Breakdown voltage of these films were about 30 volts. Using above mentioned Al2O3 film as an insulator between two aluminum electrodes, CCD transversal low pass filter has been fabricated. CCD transversal low pass filter with 17 tap coefficients has shown 22 dB stop-band attenuation. The operating clock frequency range of the fabricated device was from 3 KHz to 100 KHz.

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A Design of CPW Band-Pass Filter with Rejection Band for Ultra-Wideband System (저지 대역을 갖는 UWB용 CPW 대역 통과 여파기의 설계)

  • No, Jin-Won;Hwang, Hee-Yong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.7
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    • pp.704-709
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    • 2007
  • In this paper, a CPW band-pass filter with a rejection band is proposed for UWB(Ultra-Wideband) communication systems. The proposed filter has a band-pass characteristic of wide-band by inserting only a slot in $50{\Omega}$ transmission line. To obtain the band-rejection function at WLAN frequency band($5.15{\sim}5.725GHz$), the designed filter is combined with folded slot resonators on the ground plane of the CPW structure. The fabricated CPW band-pass filter shows a compact size of $15.35{\times}13.60mm$, a wide passband of 2.8 GHz to 9.8 GHz and the narrow stop-band of 5.15 GHz to 5.71 GHz for 3-dB bandwidth. Also, the measured group delay is less than 400 psec throughout the operation frequency band except the rejection band.

Design of Dual Band-Notched UWB Antenna with the Hilbert-Curve Slots (힐버트 곡선 슬롯을 이용한 이중 대역 저지 UWB 안테나 설계)

  • Kim, Dang-Oh;Kim, Che-Young
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.12
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    • pp.1184-1187
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    • 2011
  • In this letter, a planar monopole UWB antenna with dual band-notched characteristics is proposed. The band-stop characteristics is realized by embedding the 1st/3rd order Hilbert-curve slots on the patch. With the dimension adjustment of each Hilbert-curve slots, the band rejection from 3.3 to 3.7 GHz and from 5.3 to 6 GHz can be accomplished easily. The VSWR and radiation pattern of the fabricated antenna are measured, and the proposed antenna would be adequate to a UWB applications.

A Design and Construction of Digital Filter (디지탈 필터의 설계와 구성)

  • Lee, Dae-Yeong;Jin, Yong-Ok;Heo, Do-Geun
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.17 no.4
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    • pp.11-17
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    • 1980
  • This paper describes realization of digital filter using $\mu$p controler and discusses measured characteristics of this filter, The idea of P. L. implementation[1] is used in realization, and in this system we utilize a DMA and arithmatic control program of $\mu$p. In this way, we can get more flexible capability than the basic PL method, and higher speed than a filter using general purpose $\mu$p in hardware, Furthermore, we get a 15 KHz sampling frequency(fs) as speed limit in real time processing, and know that this limitation is restricted by execution time (58$\mu$ sec) of DMA control statement. As for filter charateristics, maximum stop band frequencies (fsp) are 1665 Hz, 1445 Hz in Butterworth and Tchebichef approximation, respectively, when fs = 14 KHz. Measured errors between the design specification and the actual result are 0.2dB, 0.1 dB in pass band (when cufoff frequency is 500Hz),-1.1dB (when fsp is 1000Hz), 0.4dB(when fsp is 750 Hz) in stop band frequency of Butterworth and Tchebichef, respectively.

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Design of Waveguide Low Pass Filter using Rectangular Rings and Ridges (직사각형 링과 리지 구조를 이용한 도파관 저역통과 여파기 설계)

  • Oh, Taek-Kyun;Choi, Hak-Keun;Lee, Hyoung-Ki
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.1
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    • pp.7-13
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    • 2014
  • In this paper, a novel waveguide low pass filter for satellite communication is proposed. The proposed low pass filter is designed to obtain wideband characteristics without the interference of higher order modes, sufficient attenuation in the stop-band and small sized lightweight characteristics by evanescent-mode ridge structure. To improve return loss and rejection loss, rectangular ring is inserting around the ridges in the waveguide. Input and output ports of the low pass filter is designed by using the impedance step structure for the impedance matching of the filter. The proposed waveguide low pass filter is fabricated and then measured as return loss over 19.5 dB, insertion loss less than 1.41 dB at the pass-band of 7.25 ~ 8.4 GHz and rejection loss over 67.2 dB at the stop-band of 12.25 ~ 14.5 GHz.

A Dynamically Segmented DCT Technique for Grid Artifact Suppression in X-ray Images (X-ray 영상에서 그리드 아티팩트 개선을 위한 동적 분할 기반 DCT 기법)

  • Kim, Hyunggue;Jung, Joongeun;Lee, Jihyun;Park, Joonhyuk;Seo, Jisu;Kim, Hojoon
    • KIPS Transactions on Software and Data Engineering
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    • v.8 no.4
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    • pp.171-178
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    • 2019
  • The use of anti-scatter grids in radiographic imaging has the advantage of preventing the image distortion caused by scattered radiation. However, it carries the side effect of leaving artifacts in the X-ray image. In this paper, we propose a grid line suppression technique using discrete cosine transform(DCT). In X-ray images, the grid lines have different characteristics depending on the shape of the object and the area of the image. To solve this problem, we adopt the DCT transform based on a dynamic segmentation, and propose a filter transfer function for each individual segment. An algorithm for detecting the band of grid lines in frequency domain and a band stop filter(BSF) with a filter transfer function of a combination of Kaiser window and Butterworth filter have been proposed. To solve the blocking effects, we present a method to determine the pixel values using multiple structured images. The validity of the proposed theory has been evaluated from the experimental results using 140 X-ray images.

Ultra-Wideband Band Pass Filter with Controllable Dual Notched Bands Using the CRLH Stubs (CRLH-Stub를 이용한 이중대역 저지 초광대역 대역통과 여파기)

  • Jung, Seung-Back;Yang, Seung-In
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.7
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    • pp.65-70
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    • 2012
  • In this paper, a compact UWB (Ultra Wideband) BPF(Band-Pass Filter) with dual notched bands is proposed using a hybrid Composited Right-Left Handed (CRLH) and Defected Ground Structure (DGS). To avoid the interferences such as Wireless LAN (Center frequency: 2.4GHz and 5.8GHz), the CRLH is employed to obtain the dual notched bands and the DGS is used to obtain the wide stop-band above the pass-band. The fabricated filter has good performance and has more than 30dB rejection at the center frequency of 2.4 GHz and 5.8GHz. The dual notched bands are easily movable by changing the CRLH parameter. Also the insertion loss is less than 0.4dB in the lower pass-band and 0.7dB in the upper pass-band, and it has small group delay variation less than 0.6ns. The size of the fabricated filter is very compact (17mm*17mm).