• 제목/요약/키워드: Band Rejection

검색결과 245건 처리시간 0.023초

Doherty Amplifier Using Load Modulation and Phase Compensation DGS Micro-Strip Line (부하 변조 및 위상 보상 DGS 마이크로스트립 선로를 이용한 도허티 증폭기)

  • Choi Heung-Jae;Lim Jong-Sik;Jeong Yong-Chae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • 제16권8호
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    • pp.815-824
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    • 2005
  • In this paper, we proposed a new DGS(Defected Ground Structure) Doherty amplifier for IMT-2000 band. Originally, active load-pull analysis of a Doherty amplifier assumes ideal harmonic termination condition. However, there have been no papers considering this ideal harmonic termination condition. We obtained excellent improvements of efficiency, gain, maximum output power as well as superior size reduction of a Doherly amplifier by satisfying the overlooked assumption of ideal harmonic termination through the adaptation of DGS at the output transmission line of carrier and peaking amplifier that is essential for Doherty operation. The amount of both the 2nd and the 3rd harmonic rejection of the proposed DGS Doherty amplifier over the conventional one are 44.92 dB and over 23.77 dB, respectively. The acquired improvement in Pl dB, gain, drain efficiency, and ACPR to WCDMA 1FA signal were 0.42 dB, 0.33 dB, $6.4\%$ and 5.4 dBc, respectively. Moreover, electrical length of $90{\circ}$ is reduced at each of the DGS carrier amplifier path and DGS peaking amplifier path, therefore the whole amplifier circuit size is considerably reduced.

Millimeter-wave LTCC Front-end Module for Highly Integrated Transceiver (고집적 송수신기를 위한 밀리미터파 LTCC Front-end 모듈)

  • Kim, Bong-Su;Byun, Woo-Jin;Kim, Kwang-Seon;Eun, Ki-Chan;Song, Myung-Sun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • 제17권10호
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    • pp.967-975
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    • 2006
  • In this paper, design and implementation of a very compact and cost effective front-end module are presented for IEEE 802.16 FWA(fixed Wireless Access) in the 40 GHz band. A multi-layer LTCC(Low Temperature Co-fred Ceramic) technology with cavity process to achieve excellent electrical performances is used to fabricate the front-end module. The wirebond matching circuit design of switch input/output port and waveguide transition to connect antenna are optimally designed to keep transmission loss low. To reduce the size of the front-end module, the dielectric waveguide filter is developed instead of the metal waveguide filter. The LTCC is composed of 6 layers(with the thickness of a layer of 100 um) having a relative dielectric constant of 7.1. The front-end module is implemented in a volume of $30{\times}7{\times}0.8mm^3$ and shows an overall insertion loss < 5.3 dB, and image rejection value > 49 dB.

SOI CMOS Miniaturized Tunable Bandpass Filter with Two Transmission zeros for High Power Application (고 출력 응용을 위한 2개의 전송영점을 가지는 최소화된 SOI CMOS 가변 대역 통과 여파기)

  • Im, Dokyung;Im, Donggu
    • Journal of the Institute of Electronics and Information Engineers
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    • 제50권1호
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    • pp.174-179
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    • 2013
  • This paper presents a capacitor loaded tunable bandpass chip filter using multiple split ring resonators (MSRRs) with two transmission zeros. To obtain high selectivity and minimize the chip size, asymmetric feed lines are adopted to make a pair of transmission zeros located on each side of passband. Compared with conventional filters using cross-coupling or source-load coupling techniques, the proposed filter uses only two resonators to achieve high selectivity through a pair of transmission zeros. In order to optimize selectivity and sensitivity (insertion loss) of the filter, the effect of the position of asymmetric feed line on transmission zeros and insertion loss is analyzed. The SOI-CMOS switched capacitor composed of metal-insulator-metal (MIM) capacitor and stacked-FETs is loaded at outer rings of MSRRs to tune passband frequency and handle high power signal up to +30 dBm. By turning on or off the gate of the transistors, the passband frequency can be shifted from 4GH to 5GHz. The proposed on-chip filter is implemented in 0.18-${\mu}m$ SOI CMOS technology that makes it possible to integrate high-Q passive devices and stacked-FETs. The designed filter shows miniaturized size of only $4mm{\times}2mm$ (i.e., $0.177{\lambda}g{\times}0.088{\lambda}g$), where ${\lambda}g$ denotes the guided wave length of the $50{\Omega}$ microstrip line at center frequency. The measured insertion loss (S21)is about 5.1dB and 6.9dB at 5.4GHz and 4.5GHz, respectively. The designed filter shows out-of-band rejection greater than 20dB at 500MHz offset from center frequency.

A Bandstop Filter Using C-DGS(Coupled-Defected Ground Structure) and the Mixer Application (결합된 결함 접지면 구조(C-DGS)를 이용한 대역 저지 여파기 및 믹서 응용)

  • Jung, Sang-Woon;Jang, Jae-Won;Lim, Young-Kwang;Lee, Hai-Young
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • 제18권9호
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    • pp.1039-1046
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    • 2007
  • In this paper, a coupled-defected ground structure(C-DGS) using negative inductive coupling is proposed and a bandstop filter(BSF) using C-DGS is designed and fabricated. The proposed C-DGS is the closely-located DGS cells for the negative coupling, the negative coupling of ground currents between adjacent DGS cells greatly improves the stopband characteristics. The proposed BSF utilizing the sharp cutoff response of the C-DGS has a -10 dB rejection band from 4 GHz to 11.3 GHz. A maximum attenuation rate is -64.3 dB/GHz in 3 cell structure, -108 dB/GHz in 5 cell structure. The C-DGS BSF shows the improved attenuation rate 3.8 times in 3 cell structure, 2.4 times in 5 cell structure, Also, the C-DGS BSF is reduced to 35.2 % and 40 % of the DGS BSF, respectively, due to the closely-located DGS cells. We fabricated the single gate mixer using C-DGS BSF. The single gate mixer has 6.6 dB conversion gain.

Transforming the Wongaksa Bell[Buddhist Bell] to the Bosingak Bell[Court Bell]: An Example of the Debuddhismization during the Joseon Dynasty (원각사종(圓覺寺鐘)에서 보신각종(普信閣鍾)으로 -조선시대 탈불교화의 일례-)

  • Nam Dongsin
    • MISULJARYO - National Museum of Korea Art Journal
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    • 제104권
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    • pp.102-142
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    • 2023
  • The Bronze Bell of Wongaksa Temple, also known as the Bosingak Bell, was produced in 1468 during the reign of King Sejo for dedication at Wongaksa Temple in the middle of the capital Hanyang in celebration of the tenth anniversary of his accession to the throne. It is currently heavily damaged and cannot be struck. This paper focuses on the man-made damage inflicted on the Bosingak Bell and explores when, why, and by whom the bell was damaged along with the historical significance of this damage. In the first section, the relevant literature is reviewed and the problems concerned, research perspective, and methodology are presented. The history of related theories is investigated focusing on the relationship between Bosingak Bell and Wongaksa Bell. The perspective that Bosingak Bell and Wongaksa Bell are the same is introduced. My discussion will be developed from this perspective. In the second section, the background to King Sejo's construction of Wongaksa Bell is examined. Specifically, the bells commissioned by the kings of the early Joseon era are divided into court bells (jojong) and Buddhist bells (beomjong). They total four court bells and three Buddhist bells. The former are the Jongnu Tower Bell commissioned by King Taejo, Donhwamun Gate Bell by King Taejong, Gwanghwamun Gate Bell by King Sejong, and Sajeongjeon Hall Bell by King Sejo. The latter are the bells of Yongmunsa, Heungcheonsa (or Jeongneungsa) and Wongaksa Temples, all of which were made during the reign of King Sejo. Sejo also made Wongaksa Bell and gave it the meaning that the monarch and the Buddha both wish to enlighten the people through the sound of the bells. In the third section, traces of the man-made damage done to Bosingak Bell are closely examined. By observing the current condition of Bosingak Bell and comparing it with the contemporaneous Heungcheongsa Bell (1462) and Bongseonsa Bell (1469), the components of Bosingak Bell that were damaged can be identified. The damaged parts are again divided into Buddhist elements and non-Buddhist elements. The former includes the reversed lotus petals on the shoulder band, four standing bodhisattvas, and the inscription of the bell composed by Choe Hang. The latter includes lists of chief supervisors (dojejo). I describe the phenomenon of deliberately damaging Buddhist elements on bells as "effacement of Buddhism," meaning Buddhist images and inscriptions are eliminated, and I note the prevailing rejection of Buddhism theory among Neo-Confucianists as its ideological root. The erasure of non-Buddhist images was probably caused by political conflicts such as Yeonsangun's purge in 1504. Since both ideological and political factors played a role in the changes made to Bosingak Bell, the damage was possibly done between the Purge of 1504 and the abdication of Yeonsangun in 1506. Chapter four traces the transformation of the Buddhist bell of Wongaksa Temple into the Bosingak court bell. Finally completed in 1468, the Wongaksa Bell only served its role as a Buddhist bell at related services for a relatively brief period of 36 years (until 1504). Wongaksa Temple was closed down and the bell lost its Buddhist function. In 1536, it was moved from Wongaksa Temple to Namdaemun Gate, where it remained silent for the next 90 years until it was struck again in November 1594. However, after the destruction of the Jongnu Bell in a fire during the Japanese Invasions of Korea (1592-1598), the Buddhist bell from Wongaksa Temple became a court bell. The Wongaksa Temple bell was relocated to Jongnu Tower in 1619, traveling through Myeongdong Pass. From then on, as the official Jongnu Bell (later renamed Bosingak Bell), it was regularly rung at dawn and dusk every day for nearly 300 years until 1908, when Japanese authorities halted the ritual. The transformation of the Wongaksa Bell (a Buddhist bell) to Bosingak Bell (a court bell) means that the voice of the Buddha was changed to the voice of the king. The concept of "effacement of Buddhism," evident in the transformation of Wongaksa Bell to Bosingak Bell, was practiced widely on almost every manifestation of Buddhism throughout the Joseon period. In short, the damage evident in Bosingak Bell underscores the debuddhismization in Korean society during the Joseon Dynasty.