• Title/Summary/Keyword: high dielectric antennas

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Improvement of Performance of Thick High Dielectric Patch Antennas Using Photonic Bandgap Structures (포토닉 밴드갭 구조를 이용한 두껍고 큰 유전상수 패치 안테나의 성능 향상)

  • 기철식;박익모;이정일;임한조
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2001.11a
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    • pp.91-95
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    • 2001
  • This paper presents that photonic bandgap structures suppressing the propagation of surface waves can improve the performance of the patch antennas on thick high dielectric constant substrate. The forbidden propagation of surface wave due to the photonic bandgap enhances the radiation efficiency and reduce the back radiation drastically with maintaining the small size and wide bandwidth of the antennas.

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Design of internal dielectric ceramic antennas for IMT-2000 handset (IMT-2000용 단말기 내장형 유전체 세라믹 안테나 설계)

  • 심성훈;강종윤;박용욱;윤석진;윤영중;김현재
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.968-971
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    • 2001
  • In this paper, internal antennas for IMT-2000 handset(1.92∼2.17 GHz) were designed to be capable of being mounted on the circuit-board with a CPW(coplanar waveguide) feeding structure. The chip antennas were miniaturized to a greater extent by fabricating multilayer high dielectric ceramic($\varepsilon$$\sub$r/=7.8) hexahedron. The proposed antennas has λ/4 monopole element with helical structure in the multilayer dielectric ceramic hexahedron. The simulated and measured results were invesgated with width, length, and thickness of helical structure in the hexahedron.

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Improvement of Performance of Thick and High Dielectric Patch Antennas using Photonic Bandgap Structures (포토닉 밴드갭 구조를 이용한 두껍고 유전상수가 높은 패치 안테나의 성능 향상)

  • 기철실;박익모;임한조;한해욱;이정일
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.1
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    • pp.1-6
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    • 2002
  • This paper presents that photonic bandgap structures suppressing the propagation of surface waves can improve the performance of the patch antennas on a thick and high dielectric constant substrate. The forbidden propagation of surface wave due to the photonic bandgap enhances the radiation efficiency and reduces the back radiation drastically.

New Density-Independent Model for Measurement of Grain Moisture Content using Microwave Techniques

  • Kim, Jong-Heon;Kim, Ki-Bok;Noh, Sang-Ha
    • Journal of Electrical Engineering and information Science
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    • v.2 no.4
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    • pp.72-78
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    • 1997
  • A free space transmission method using standard gain horn antennas in the frequency range from 9.0 to 10.5GHz is applied to determine the dielectric properties of grain such as rough rice ,brown rice and barley. The dielectric constant and loss factor, which depend on the moisture content of the wetted grain are obtained from the measured attenuation and phase shift by vector network analyzer. The moisture content of grain varied from 11 to 25% based on this wetted condition. The measured values of dielectric constants as a function of moisture density are compared with values of those obtained using he predicted model for estimating dielectric constants of grain. The effect of density fluctuation, high is an important parameter governing the dielectric properties of grain, on the dielectric constant and loss factor is presented. A new density-independent model in terms of measured attenuation an moisture density is proposed of reducing the effects of density fluctuation on the moisture content measurement.

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Multi-Dielectric & Multi-Band operations on RF MEMS

  • Gogna, Rahul;Gaba, Gurjot Singh;Jha, Mayuri;Prakash, Aditya
    • Transactions on Electrical and Electronic Materials
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    • v.17 no.2
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    • pp.86-91
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    • 2016
  • Ever increasing demand for microwave operated applications has cultivated need for high-performance universal systems capable of working on multi-bands. This objective can be realized using Multi-Dielectrics in RF MEMS capacitive switch. In this study, we present a detailed analysis of the effect of various dielectrics on switch performance. The design consists of a capacitive switch and performance is analyzed by changing the dielectric layers beneath the switch. The results are obtained using three different dielectrics including Silicon nitride (7.6), Hafnium dioxide (25) and Titanium oxide (50). Testing of proposed switch yields high isolation (- 87.5 dB) and low insertion loss (- 0.1 dB at 50 GHz) which is substantially better than the conventional switches. The operating bandwidth of the proposed switch (DC to 95 GHz) makes it suitable for wide band microwave applications.

Design of CPW fed antenna using high dielectric constant materials (고유전율 유전체를 이용한 CPW 급전 안테나의 설계)

  • 심성훈;강종윤;윤석진;윤영중;김현재
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.559-562
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    • 2000
  • In this paper, coplanar waveguide fed antennas (CPWFAs) insetting two slits to boundary of the square microstrip patch are presented. These slits play roles in not only lowering a resonant frequency but also fine-tuning for the proposed antenna together with open stub of CPW feed line. The CPWFAs were designed and manufactured using microwave dielectrics (Al,Mg)TaO$_2$ having high dielectric-constant ($\varepsilon$r=20). The return loss and input impedance of the CPWFAs were investigated in terms of the slit length and open stub length of CPW feed line. It is shown that a resonant frequency decreases as the slit length increases.

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A High-Gain Microstrip Patch Array Antenna Using a Superstrate Layer

  • Choi, Won-Kyu;Cho, Yong-Heui;Pyo, Cheol-Sik;Choi, Jae-Ick
    • ETRI Journal
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    • v.25 no.5
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    • pp.407-411
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    • 2003
  • A dielectric superstrate layer above a microstrip patch antenna has remarkable effects on its gain and resonant characteristics. This paper experimentally investigates the effect of a superstrate layer for high gain on microstrip patch antennas. We measured the gain of antennas with and without a superstrate and found that the gain of a single patch with a superstrate was enhanced by about 4 dBi over the one without a superstrate at 12 GHz. The impedance bandwidths of a single patch with and without a superstrate for VSWR < 2 were above 11%. The designed $2{\times}8$ array antenna using a superstrate had a high gain of over 22.5 dB and a wide impedance bandwidth of over 17%.

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A Dielectric Slab Rotman Lens (유전판 로트맨 렌즈)

  • 김재흥;조춘식
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.11
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    • pp.1108-1115
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    • 2004
  • A new type of a Rotman lens is presented in this paper fur millimeter-wave applications, such as collision avoidance radar. A dielectric slab Rotman lens is proposed to reduce the conductor loss and to create an appropriate farm for favorable implementation at millimeter-wave frequency. The proposed lens consists of a dielectric slab and slot lines whereas the conventional lenses are constructed with parallel conducting plates. The dielectric slab Rotman lens excited in TE$\_$0/ mode shows a high degree of confinement for the fields, low dispersion, and has an appropriate feed structure. A prototype lens has been designed and fabricated with 9 beam ports and 9 array ports together with 9 tapered slot antennas. This lens has been tested in the range from 10 GHz to 15 GHz and the measured beam widths are about 15$^{\circ}$ at 13 GHz. The measurements also show low mutual coupling between beam ports and an efficiency of about 34.6 %. The overall performance is comparable to that of conventional Rotman lenses even though the prototype was tested at lower than desired frequencies in the microwave frequency range due to our limited resources for fabrications and measurements. It is expected that at millimeter-wave frequency the dielectric slab Rotman lens will have lower conductor loss and lower mutual coupling than conventional Rotman lenses.an lenses.

Effect of the Patch Length and Via Radius on the Radiation Characteristics of an Inductive Loaded Patch Antenna (패치의 길이와 비아의 반경이 Inductive Loaded Patch Antenna의 방사 특성에 미치는 영향)

  • Kwak, Eun-Hyuk;Yoon, Young-Min;Kim, Boo-Gyoun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.6
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    • pp.48-56
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    • 2012
  • Radiation characteristics of inductive loaded patch antennas (ILPAs) and conventional patch antennas using a half wavelength resonance mode for substrates with various dielectric constants are investigated. ILPAs have the good radiation characteristics such as high broadside gain and suppressed radiation along the horizontal plane compared to those of conventional patch antennas. We show that ILPAs with the appropriate patch length and via radius have the optimum radiation characteristics such as the highest broadside gain and the most suppressed horizontal radiation.

Telematics Antenna for Vehicles (차량용 텔레매틱스 안테나)

  • 김해연;이병제;양성현
    • Journal of the Korea Computer Industry Society
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    • v.5 no.2
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    • pp.331-336
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    • 2004
  • In this paper, an antenna for telematics is proposed. It operates at GPS/GSM frequency-bands and it can be installed inside of a vehicle. There is a great difference between the proposed antenna and commonly used antennas. It needs not to use a dielectric with a high permittivity since it is formed on a sheet of FR4 with only 1mm thickness. Thus, it is possible to cut costs and make process of manufacture simple. Planar inverted-F antenna(PIFA) for GSM and microstrip antenna(MSA) for GPS is designed and PIFA-MSA antenna is proposed. The height is lower than that of commonly used antennas. And polarization of the PIFA and MSA is arranged perpendicularly for isolation improvement of each port, thus isolation of these two antennas is improved. Also, it is sufficient for the all specifications.

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