• Title/Summary/Keyword: tri-wideband

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Compact tri-wideband bandpass filter with multiple transmission zeros

  • Xiong, Yang;Wang, LiTian;Gong, Li;He, KaiYong;Zhang, Man;Li, Hui;Zhao, XinJie
    • 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.

On the Handover Performance of a Tri-threshold Bandwidth Reservation CAC Scheme

  • Tung, Hoi Yan;Tsang, Kim Fung;Lee, Lap To;Lam, Ka Lun;Sun, Yu Ting;Kwan, Shiu Keung Ronald;Chan, Sammy
    • ETRI Journal
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    • v.29 no.1
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    • pp.113-115
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    • 2007
  • A dynamic tri-threshold call admission control scheme has been developed. This scheme supports voice, data, and multimedia services and it complies with the universal mobile telecommunications system. The performance of the proposed scheme is evaluated under varying handover rates. The QoS performance-including channel utilization, call dropping probability, and blocking probability-is investigated. The performance of the developed scheme is found to be encouraging.

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A Study on the Design of Wideband Microstrip Cross Slot Array Antennas with Circular Polarization (원편파용 광대역 마이크로스트립 크로스 슬롯 어레이 안테나의 설계에 관한 연구)

  • Min, Kyeoung-sik;Ko, Jee-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.4
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    • pp.894-900
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    • 2004
  • There are many types of circularly polarized(CP) microstrip antenna elements, which are used as a good unit radiator. Since an advantage of CP antenna is no strict alignment requirements between Rx and Tx system, the printed antennas with circular polarization are very often used in numerous satellite and mobile radio systems. In order to realize the broad bandwidth of 3 dB axial ratio and impedance of CP microstrip antenna, complex feed structure and tri-plate patch element have been researched. This paper describes a design of wideband microstrip cross slot array antennas with circular polarization. The proposed antenna is composed of an open-ended microstrip feed line as a feeder and a cross slot as a radiator for circular polarization. To realize the wide bandwidth, tri-plate structure are considered and cross slot is electromagnetically coupled with feed line. Optimum parameters of 1-element cross slot antenna are analyzed and designed by method of moments. These parameters are also applied to may antennas design considered the mutual coupling between radiating elements. Right hand circular polarization(RHCP) and left hand circular polarization(LHCP) of the proposed antenna are easily controlled by asymmetrical cross slot structure and slot position. In 1-element and 15-element cross slot array antenna, the good axial ratio of 1 dB below and the broad bandwidth characteristics of antenna are obtained.