• Title/Summary/Keyword: Return loss

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A Design for a CPW-Fed Monopole Antenna with Two Modified Half Circular Rings for WLAN/WiMAX Operations

  • Kim, Woo-Su;Yoon, Joong-Han
    • Journal of information and communication convergence engineering
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    • v.13 no.3
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    • pp.159-166
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    • 2015
  • In this paper, a novel design for a triple-band coplanar waveguide (CPW)-fed monopole antenna for WLAN/WiMAX operations is proposed. The proposed antenna is printed on an FR4 substrate with an area of 22.0 mm × 30.0 mm, a thickness of 1.0 mm, and a relative permittivity of 4.4. The effects of various parameters of the proposed for triple band operation is investigated. Two half circular rings and a microstrip feed line are fabricated on the substrate to achieve triple band operation and good impedance matching. Prototypes of the proposed antenna have been fabricated and tested. Experiment results reveal that the measured return loss exhibits an acceptable agreement with the simulated return loss and satisfies the impedance bandwidth requirement of -10 dB, while simultaneously covering the WLAN and WiMAX bands. In addition, the proposed antenna shows good radiation characteristics and gains in the three operating bands.

A Method to Improve Bragg Reflectors Quality in FBAR Devices

  • Mai, Linh;Lee, Jae-Young;Pham, Van Su;Yoon, Gi-Wan
    • Journal of information and communication convergence engineering
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    • v.5 no.4
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    • pp.316-319
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    • 2007
  • This paper presents some methods to improve the resonance characteristics of film bulk acoustic-wave resonator (FBAR) devices. The FBAR devices were fabricated on multilayer Bragg reflectors (BR) into which very thin chromium (Cr) adhesion layers were inserted, followed by several kinds of thermal annealing processes. These methods resulted in an excellent device improvement in terms of return loss and Q-factors.

Improvement of Resonance Characteristics by Post-Annealing in FBAR Devices

  • Lee, Jae-Young;Mai, Linh;Yoon, Gi-Wan
    • Journal of information and communication convergence engineering
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    • v.5 no.4
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    • pp.320-323
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    • 2007
  • This paper presents the resonance characteristics of the ZnO-based FBAR devices with multilayered Bragg reflectors with Cr adhesion layer inserted between $SiO_2$ and W layers. Due to the post- annealing, the return loss ($S_{11}$) and series/parallel quality factor are significantly improved when compared with the non-post annealing. This post-annealing method seems to be a very efficient way to improve the resonance characteristics of FBAR devices.

Realization of FBAR Devices for Broadband WiMAX Applications

  • Mai, Linh;Lee, Jae-Young;Pham, Van Su;Yoon, Gi-Wan
    • Journal of information and communication convergence engineering
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    • v.6 no.1
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    • pp.34-37
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    • 2008
  • Effects of the addition of Cr adhesion layer to $W/SiO_2$ multilayer Bragg reflectors on the resonance characteristics of film bulk acoustic wave resonator (FBAR) devices are presented. Main resonance peaks could be significantly shifted to higher frequency, mainly due to the addition of Cr adhesion layer to multilayer Bragg reflectors and control of the bottom electrode thickness as well. The FBAR devices with the Cr adhesion layer in Bragg reflectors could result in much more improved resonance characteristics at about 3 GHz in terms of return loss and Q-factor.

Design of Wideband Microstrip Patch Antenna (광대역 마이크로스트립 패치 안테나 설계)

  • Kim, Tae Yong;Lee, Jong-Ig
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.05a
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    • pp.469-470
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    • 2015
  • General microstrip patch antenna has small bandwidth. Also this patch antenna is strongly influenced by the thickness of dielectric substrate and its relative permittivity. In this paper, wideband microstrip patch antenna operating in 2.4GHz ISM band is studied. Input impedance and return loss for designed microstrip patch antenna by using MoM method and is estimated.

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A Study on Frequency Properties of Bulk Acoustic Wave Resonators using PVDF (고분자 압전필름을 이용한 BAW 공진기의 주팍수 특성에 관한 연구)

  • 정영학;김응권;윤창진;송준태
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.12
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    • pp.1077-1079
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    • 2003
  • This paper describes the development of bulk acoustic wave (BAW) resonators using a PolyVinyliDene Fluoride (PVDF). The resonators have an air gap between a substrate for acoustic isolation without surface micromachining. We measured the resonance frequency and the input reflection coefficient (S$\sub$11/) of resonators using vector network analyzer. The fundamental resonance in this experimental result was measured at 1.4 ㎓ with a return loss of -23.2 ㏈. We can confirm a possibility of resonator application as using a PVDF because it can fabricate the resonator without etching process.

A Study on Frequency Property of Bulk Acoustic Wave Resonator Using PVDF (고분자 압전필름을 이용한 Bulk Acoustic Wave Resonator의 주파수 특성에 관한 연구)

  • Jeong, Young-Hak;Kim, Eun-Kwon;Yun, Chang-Jin;Lee, Kyu-Ill;Lee, Jong-Duk;Song, Joon-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.673-676
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    • 2003
  • This paper describes the modeling and experimental results for Bulk Acoustic Wave(BAW) Resonator using PolyVinyliDene Fluoride(PVDF). We measured the input reflection coefficient ($S_{11}$) of resonators using vector network analyzer and experimental results were measured fundamental resonance at 2.3 GHz with a return loss of -29 dB. Because of fabricated resonator without etching process, we can confirm a possibility of resonator application as using a PVDF.

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Effects of PCB Ground Plane and Case on Internal WLAN Patch Antenna

  • Kim, H.T.;Heo, J.K.;Jeong, K.J.;Hwang, S.W.
    • Journal of IKEEE
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    • v.11 no.4
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    • pp.252-256
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    • 2007
  • We demonstrate that the effect of the PCB ground length and the cover is important in the performance of 2.4 GHz patch antennas. The Center frequency in the return loss shifts as much as 0.5 GHz, when the length of the PCB ground increases from 30 to 85 mm. The position of 10-dB bandwidth accordingly shifts to lower frequency region. Finally, the resonance at 2.4 GHz becomes stronger when the top cover exists. The radiation pattern of the patch antenna is also strongly affected by the ground structure and the existence of the top cover. In both the return loss and the radiation pattern, 3-dimensional simulations are shown to be an efficient tool.

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Semi-rigid Coaxial Cable Antenna for RTA (RTA용 반강체 동축케이블 안테나)

  • 강철준;박성교;문장원;박종백
    • Proceedings of the IEEK Conference
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    • 2003.07a
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    • pp.262-265
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    • 2003
  • Radiofrequency thermal ablation (RTA) as one of the microwave hyperthermia is becoming the treatment of choice for small but inoperable tumors of the liver. In this paper, we designed the applicator composed of semi-rigid coaxial cable antenna with a ring slot for RTA. To optimize the maximum output of radiation at 2450 MHz, we simulated the antenna using Electromagnetic simulation tools Maxwell program and analyzed the return loss and the electric field $E_{tot}$ at the near-field region between the simulation results and measurement results. As a result, we obtained the return loss of -29.786 dB at 2450 MHz when the antenna was placed between two blocks of a pig's liver, and the measurement results agreed with the simulation results well. Therefore, this semi-rigid coaxial cable antenna with a ring slot can be used very usefully as the applicator for RTA.r RTA.A.

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Improved Method for Calculating Radiation Admittance of a Rectangular Microstrip Patch Antenna (구형 마이크로스트립 안테나의 개선된 복사 어드미턴스 계산방법)

  • Hong, Jae-Pyo;Cho, Young-Ki;Son, Hyon
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.2
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    • pp.35-40
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    • 1989
  • In this paper, a new method which simultaneously gives the radiation conductance and susceptance of the rectangular microstrip patch antenna. This solution is derived from the load admittance of the equivalent ${\pi}-$network circuit of the slitted parallel-plate waveguide filled with homogeneous dielectric. Our theoretical results for the radiation admittance are compared with other theoretical results. Also, our theoretical return loss and resonant frequency which are calculated by use of the equivalent transmission line model are in fairly good agreement with the experimental results.

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