• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.151-156
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• 2021

Leakage and Bragg condition of optical waveguide with asymmetric rectangular grating profile are evaluated in detail by using novel and rigorous modal transmission-line theory (MTLT) based on eigenvalue problem. The optical waveguide composed by asymmetric rectangular grating occur leaky-wave stop-bands at Bragg conditions, and anomalies based on Rayleigh-Wood condition near Bragg conditions. Furthermore, DFB properties of the guiding structure at Bragg conditions are analyzed by applying longitudinal equivalent transmission-line with characteristic impedance of periodic grating. The numerical results show that filtering characteristics that maximize the reflected power of DFB waveguide are activated near Bragg conditions, in which leaky-wave stop-bands occur.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.12
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• pp.8-13
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• 1997

In this paper, the input impedance and efficiency of rectangulr microstip patch antenna located inside a rectangular wavegudie is calculated by using the cavity model and the mode excited by te patch antenna which is modeled as an equivanlent surface magnetic current on the conducting plate. Measured return losses of a rectangular microstrip patch antenna tuned at 5.93 GHz in the free space and inside the retangular waveguide are compared and found to be in good agreement with calculated results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.119-126
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• 2008

In this paper, the loop coupling model for the analysis of end launcher rectangular waveguide adapter are proposed. The formula of input impedance from this model are presented. The influence of propagation mode and higher modes in rectangular waveguide are analyzed and design parameters of the end launcher adapter are investigated. The computational results between the proposed theoretical analysis and the previous papers are compared and are verified by HFSS. The end launcher rectangular waveguide adapter consists of the coupling geometry which is connected the inner conductor of $50{\Omega}$ coaxial line through into the 17.6mm feeding loop in a WR90 commercial waveguide, and the VSWR is maximum 2.0 over operating frequency from 7.5GHz to 10.6GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.698-705
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• 2004

In this paper, we present the analysis method for a rectangular waveguide with horizontal conducting post using mode matching method and generalized scattering method. Scattering characteristics of a rectangular waveguide with the horizontal conducting post according to radius and height of the post are simulated by the proposed method. The simulated results by proposed method show good agreement with the measured results and the HFSS's results. Proposed method are easily applied to the design of a waveguide component with horizontal conducting posts.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.4
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• pp.42-47
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• 1999

Based on characteristics of resonator in BPF, a resonant characteristic is obtained by using variation of characteristic impedance in rectangular waveguide. And we have designed and made a novel waveguide BPF with this phenomenon. This filter can be made with arbitrary lengths of rectangular waveguide resonators.

• Journal of electromagnetic engineering and science
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• v.4 no.4
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• pp.150-155
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• 2004

Universal design equations are presented for the H-plane T-junction power divider with a circular conducting post in a rectangular waveguide. For a given operating frequency and power split ratio, the post offset from the T-junction center line, the distance between the post and the waveguide wall, and the post diameter can be adjusted to obtain a minimum reflection at the input waveguide. Optimum values of the post offset are given in terms of the normalized frequency and the power split ratio. Corresponding values of the post diameter and the distance of the post from the waveguide wall are given in terms of the normalized frequency and the post offset.

• Journal of Sensor Science and Technology
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• v.10 no.1
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• pp.71-79
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• 2001

The use of a glass-plate probe of rectangular shape is proposed for the measurement of transmission loss in optical waveguides. The light-collecting window is of a thin, rectangular shape and is perpendicular to the light streak, while the conventional fiberglass probe has a small circular face. This transversely elongated form results in a grate improvement of mechanical tolerance for the probe movement in the vortical as well as in the transverse direction. A theoretical investigation also presents a reasonable agreement with the experiments.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.406-412
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• 2018

In this paper, we propose a narrow resonant waveguide probe that can improve the measurement sensitivity in near-field scanning microwave microscopy. The probe consists of a metal waveguide incorporating the following two sections: a straight section at the tip of the probe whose cross-section is a double-ridged rectangle, and whose height is much smaller than the waveguide width; and a standard waveguide section. The advantage of the narrow waveguide is the same as that of the quarter-wave transformer section i.e., it achieves impedance-matching between the sample under test (SUT) and the standard waveguide. The design procedure used for the probe is presented in detail and the performance of the designed resonant probe is evaluated theoretically by using an equivalent circuit. The calculated results are compared with those obtained using the finite element method (Ansoft HFSS), and consistency between the results is demonstrated. Furthermore, the performance of the fabricated resonant probe is evaluated experimentally. At X-band frequencies, we have measured the one-dimensional scanning reflection coefficient of the SUT using the probe. The sensitivity of the proposed resonant probe is improved by more than two times as compared to a conventional waveguide cavity type probe.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8A
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• pp.962-971
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• 2004

In this paper, we present the numerical analysis method for analyzing scattering characteristics of a rectangular waveguide with the conducting half cylinder using the mode matching method and compute scattering characteristics of a waveguide according to the rotation and changing radius of the half cylinder. Also, in conjunction with the generalized scattering method, the proposed method can be easily applied to a rectangular waveguide with cascade structure of conducting half cylinders. From the simulated result of a two pole filter, resonance frequency could be controlled by the rotation of half cylinders. The simulated result shows good agreement with the HFSS's result. The proposed structure and analysis method are easily applied to the design of waveguide components with conducting half cylinders.

• Journal of electromagnetic engineering and science
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• v.14 no.1
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• pp.36-42
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• 2014

In this paper, an epsilon near zero (ENZ) tunneling circuit using a double-ridge rectangular waveguide (RWG) is proposed for the miniaturization of a waveguide component. The proposed ENZ channel and is located in the middle of the input-output RWG (IORWG). The ratio of the height to the width of the channel waveguide is very small compared to the IORWG. By properly adjusting the ridge dimensions, the tunneling frequency of the proposed ENZ channel can be lowered to near the cut-off frequency of the IORWG. For the proposed ENZ tunneling circuit, the approach adopted for extracting the effective permittivity, effective permeability;normalized effective wave impedance, and propagation constant from the simulated scattering parameters was explained. The extracted parameters verified that the proposed channel is an ENZ channel and electromagnetic energy is tunneling through the channel. Simulation and measurement results of the fabricated ENZ channel structure agreed.