• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 추계학술대회논문집
• /
• pp.481-482
• /
• 2008

This investigation presents a method to design an optimal shape of a matching waveguide connecting two waveguides having different impedances. The design objective is to maximize power transmission through the waveguide system. When an incident wave impinges on an elastic waveguide system consisting of waveguides of different impedances, all of the incident wave power may not pass through due to the mechanical impedance. Therefore, the maximization of the transmitted power through a waveguide difficult to achieve without a systematic design method. In this work, the optimal shape design of a matching waveguide connecting two waveguides of different impedances is formulated as a shape optimization problem. If the material of the matching waveguide is given, its shape is the only parameter controlling the transmission power. Relatively simple one dimensional elastic wave transmission problems will be considered in this work, but the underlying methodology and the related physics can be clearly demonstrated. The influences of initial configurations as well as the target frequencies on the optimized shapes will be also investigated.

• Journal of electromagnetic engineering and science
• /
• 제5권3호
• /
• pp.140-145
• /
• 2005

In this paper, an experimental investigation for return loss and a software-based prediction for interference level of single-packaged filtering antenna composed of dielectric waveguide filter and PCB(Printed Circuit Board) slot antenna in transceiver module have been carried out with several different feeding structures in millimeter-wave regime. The implementation and embedding method of the existing air-filled waveguide filters working at millimeter-wave frequency on general PCB substrate have been described. In a view of the implementation of each components, the dielectric waveguide embedded in PCB and LTCC(Low Temparature Co-fired Ceramic) substrates has employed the via fences as a replacement with side walls and common ground plane to prevent energy leakage. The characteristics of several prototypes of filtering antenna embedded in PCB substrate are considered by comparing the wideband and transmission characteristics as a function of bent angle of transmission line connecting two components. In addition, as an essential to the packaging of transceiver module working at millimeter-wave, miniaturization technology maintaining the performances of independent components and the important problems caused by integrating and connecting the different components in different layers are described in this paper.

• Journal of the Optical Society of Korea
• /
• 제12권3호
• /
• pp.162-165
• /
• 2008

A novel planar lightwave circuit(PLC) triplexer using a three-waveguide interferometer(TWI) is proposed and examined using the transfer matrix and the beam propagation methods. The proposed triplexer consists of two three-waveguide couplers and three waveguides connecting the couplers. Simulation for the TWI triplexer shows the excess losses of 0.03 dB and 0.94 dB with the crosstalks of -22.3 dB and -14.5 dB in reception, respectively, for the wavelength of 1490- and 1550-nm, while showing the excess loss of 1.75 dB in transmission for the wavelength of 1310 nm. The proposed design shows compact feature as short as 11.5 mm for the refractive-index contrast of 0.45%.

• 한국산학기술학회논문지
• /
• 제16권9호
• /
• pp.6221-6226
• /
• 2015

광통신시스템에서 효율적인 광전송을 위해서는 광섬유와 필름 도파로사이에 효율적인 결합이 필요하다. 광섬유와 필름 도파로를 직접연결하면 광섬유와 필름 도파로간의 크기 및 모양의 차이로 인한 필드 프로필의 불일치로 인하여 연결부위에서 많은 광손실이 발생하기 때문에 광효율이 저하된다는 문제점이 존재한다. 이에 본 논문에서는 광섬유와 광도파로의 직접 연결 시 발생하는 효율의 저하를 막기 위해 광섬유와 광도파로를 연결하는 Y-branch를 설계하고 제작하였다. Y-branch의 해석방법으로는 많은 광도파로의 해석법 중 가장 간단하고 적용이 쉬운 섭동궤환방법을 사용하였다. 해석된 결과를 이용하여 $LiNbO_3$ 에 Ti를 확산시키는 방법을 통하여 Y-branch를 제작하여 측정을 실시하였다. 측정은 $1550{\mu}m$ LD레이저 광원을 이용하여 커플러를 통하여 광이 입사하도록 구성한 후 출련단에서 광신호의 near field mode를 측정하였다. 이를 통하여 Y-branch를 통해 입사하는 광의 입사조건을 변화시켜도 고차모드들은 모두 제거되고 기본 모드만 유지되고 있는 특성을 확인하였다.

• ETRI Journal
• /
• 제36권5호
• /
• pp.841-846
• /
• 2014

This study proposes a novel optical sensor structure based on a refractometer combining a bend waveguide with an air trench. The optical sensor is a $1{\times}2$ splitter structure with a reference channel and a sensing channel. The reference channel has a straight waveguide. The sensing channel consists of a U-bend waveguide connecting four C-bends, and a trench structure to partially expose the core layer. The U-bend waveguide consists of one C-bend with the maximum optical loss and three C-bends with minimum losses. A trench provides a quantitative measurement environment and is aligned with the sidewall of the C-bend having the maximum loss. The intensity of the output power depends on the change in the refractive index of the measured material. The insertion loss of the proposed optical sensor changes from 3.7 dB to 59.1 dB when the refractive index changes from 1.3852 to 1.4452.

• 전기학회논문지
• /
• 제61권10호
• /
• pp.1477-1482
• /
• 2012

This paper deals with a new variable microwave power distributor and a connector between a deck plate and a input power waveguide for indoor microwave wireless power transmission. We design a new type connector built in the 3-stage coaxial line structure, and calculate the return loss of the connector at 2.45GHz. Newly designed connector shows the excellent return loss performance less than -30dB at the operating frequency of 2.45GHz. And we show a power distributor in which the dividing ratio of the power is controlled mechanically by three rotary fins. The distributor can control the dividing power from 4.5% to 58% with the variance of 5% output power. The experimentally tested results of the distributor are good agreement with the simulation within the return loss of 1%.

• 전자공학회논문지A
• /
• 제32A권6호
• /
• pp.787-798
• /
• 1995

We implement the E-plane T-juncition manifold mutiplexer having low insertion loss for output multiplexer of Ku-band satellite transponder. Manifold multiplexer implemented here is composed of 2 channel filters, T-junctions, half-wave waveguide connecting channel filters and manifold, and manifold itself.[1-4] Considering the mass and volume of the satellite transponder, the channel filters are designed to dual-mode.[5-13] And Elliptic filter function is used, which has good characteristics of suppressing the interference between 2 channels. Since the performance of manifold multiplexer depends on the manifold waveguide transmission line length, it's necessary proper analysis. In this paper, we do optimization process of T-junction and other elements by using CAD and implement the manifold multiplexer. An experiment shows that characteristic response of multiplexer matches wel its modeling result.

• 전자공학회논문지A
• /
• 제30A권4호
• /
• pp.1-10
• /
• 1993

This paper presents the designing/manufacturing scheme of the diplexer for satellite transponder which is composed of 2-channel bandpass filters, coupled with E-plane T-junction, having symmetrical waveguide E-plane step discontinuity structures. The 2-channel bandpass filters of the diplexer are designed by the scheme of connecting ${\lambda}_{g}$/2 shunt stub to the waveguide E-plane, playing the role of heat sinks without attaching a special heat sinks and to give the profitable productivity and allow the low-cost manufacturing at mass production, tuning screws are eliminated which have been used to compensate the operating characteristics of manufactured filters. The 2 channel bandpass filters of manufactured 14/12 GHz diplexer for domestic Ku-band satellite transponder have the return loss of 25 dB, insertion loss of 0.3 dB in passband, and below-50 dB of stopband characteristics (T$_{x}$ : f$_{o}{\pm}$250 MHz, R$_{x}$ : f$_{o}{\pm}$220 MHz) at room temperature.

• Current Optics and Photonics
• /
• 제6권3호
• /
• pp.323-331
• /
• 2022

Electro-optic modulator (EOM) takes a vital role in connecting the electric and optical fields. Here, we present a heterogeneously integrated EOM based on the lithium niobate-on-insulator (LNOI) platform. The key modulation waveguide structure is a field-enhanced slot waveguide formed by embedding silicon nanowires in a thin-film lithium niobate (LN), which is different from the previously reported LN ridge or etchless LN waveguides. Based on such slot structure, optical mode field area is reduced and enhanced electric field in the slot region can interact well with LN material with high Electro-optic (EO) coefficient. Therefore, the improvements in both aspects have positive effects on enhancing the modulation performance. From results, the corresponding EOM by adding such modulation waveguide structure achieves better performance, where the key half-wave-voltage-length product (V_𝜋L) and 3 dB EO bandwidth are 1.78 V·cm and 40 GHz under the electrode gap width of only 6 ㎛, respectively. Moreover, Lower V_𝜋L can also be achieved. With these characteristics, such field-enhanced waveguide structure could further promote the development of LNOI-based EOM.

• ETRI Journal
• /
• 제45권2호
• /
• pp.338-345
• /
• 2023

A filtering power divider based on air-filled substrate-integrated waveguide (AFSIW) technology is proposed in this study. The AFSIW structure is used in the proposed filtering power divider for substantially reducing the transmission losses. This structure occupies a large area because of the use of air as a dielectric instead of typical dielectric materials. A filtering power divider provides power division and frequency selectivity simultaneously in a single device. The proposed filtering power divider comprises three AFSIW cavities. The filtering function is achieved using symmetrical inductive posts. The input and output ports of the proposed circuit are realized by directly connecting coaxial lines to the AFSIW cavities. This transition from the coaxial line to the AFSIW cavity eliminates the additional transitions, such as AFSIW-SIW and SIW-conductor-backed coplanar waveguide, applied in existing AFSIW circuits. The proposed power divider with a second-order bandpass filtering response is fabricated and measured at 5.5 GHz. The measurement results show that this circuit has a minimum insertion loss of 1 dB, 3-dB fractional bandwidth of 11.2%, and return loss exceeding 11 dB.