• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.6
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• pp.263-267
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• 2004

A new type of interaction circuitry for a broadband gyro-TWT is presented in this paper. A method for the analysis of dispersion characteristics of a periodic structure, which is composed of conducting posts in a rectangular waveguide, is presented. This method utilizes a mode matching technique and equivalent circuit model. The calculated and measured results demonstrate that this periodic structure could be utilized for the interaction circuit of a wide band Gyro-TWT.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.59-65
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• 2000

This paper describes the characteristics of a one dimensional narrow-wall slotted waveguide array with a single-layer linear-to-circular polarization converter consisting of a dipole array. An external boundary value Problem of one slot and three dipoles, which approximates the mutual coupling between the dipole array and an edge slot extending over three faces of a rectangular waveguide, is formulated and analyzed by the method of moments; design of polarization conversion is conducted for this model as a unit element. If every unit element has perfect circular polarization, grating lobes appear in the array pattern due to the alternating slot angle: these are suppressed in this paper by changing the dipole angle and degrading the axial ratio of the unit element. The validity of the design is confirmed by the measurements. The dipole array has negligible effects upon slot impedance; the polarization conversion for existing narrow-wall slotted arrays is realized by add-on dipole array.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2819-2827
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• 1997

A dielectric waveguide structure using rectangular dielectic strip is analyzed directly in terms of the wave equation for quasi TE and quasi TE and quasiTM modes. This problem can be solved, with no approximation in the wave equation for the electric field $\vec{E}$ and magnetic field $\vec{H}$ inside and outside the dielectric rectangular waveguide matching the boundary conditions between interfaces. This leads to an eigenvalue problem where spurious modes do not appear. Dispersion characeristic examples are presented for square and rectangular waveguides. The formulation is general and can be used for compuarison with ogher methods such as FDM or FEM in various structures.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.143-146
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• 1989

Narrowband bandpass waveguide filters using inducive post obstacles are designed and constructed to have an equal-ripple bandwidth of 50MHz at a center frequency of 9GHz. Both the triple-post and the single-post configurations are realized and compared. The measured results for both filters show good agreement with the theoretical calculations. When the two filters are compared, the performance of the triple-post filter is better than that of the single-post filter.

• ETRI Journal
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• v.32 no.2
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• pp.195-203
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• 2010

A new vertical transition between a substrate integrated waveguide in a low-temperature co-fired ceramic substrate and an air-filled standard waveguide is proposed in this paper. A rectangular cavity resonator with closely spaced metallic vias is designed to connect the substrate integrated waveguide to the standard air-filled waveguide. Physical characteristics of an air-filled WR-22 to WR-22 transition are compared with those of the proposed transition. Simulation and experiment demonstrate that the proposed transition shows a -1.3 dB insertion loss and 6.2 GHz bandwidth with a 10 dB return loss for the back-to-back module. A 40 GHz low-temperature co-fired ceramic module with the proposed vertical transition is also implemented. The implemented module is very compact, measuring 57 mm ${\times}$ 28 mm ${\times}$ 3.3 mm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.1
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• pp.110-118
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• 2004

In this paper, a method is presented for the design of an orthomode transducer(OMT) operating at 21/31GHz frequency bands. A square waveguide is used in the common port while the WR-34 standard rectangular waveguide is used in the straight port. The straight port is connected to the common port via a multi-stage quarter-wave impedance transformer. The side port is coupled to the common port through a slot formed along the center line of the common square waveguide. An impedance transformer is employed to match the impedance of the coupling slot with that of the WR-51 waveguide at the output of the side port. Dimensions of the OMT are iteratively optimized employing the theory of waveguide. The validity of the proposed method is verified by fabricating and testing the designed orthomode transducer.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.775-782
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• 2022

In this paper, a novel small-diameter cylindrical post capacitor inserted into an evanescent-mode rectangular waveguide (EMRWG) is proposed for easier tuning. In order to feed the EMRWG, the proposed structure uses a single ridge rectangular waveguide with the same width and height as the waveguide at the input and output ends. The inserted post capacitor are made up a circular groove formed in the center of the lower part of the broad wall of the EMRWG, and a concentric cylindrical post inserted into the upper part. First, the equivalent circuit model for the proposed structure is presented. When the EMRWG and the single ridge waveguide are combined, the joint susceptance and the turns ratio of the ideal transformer are calculated by two simulations using HFSS (3d fullwave simulator, Ansoft Co.) respectively. The susceptance and resonance characteristics of the inserted post were analyzed by using the obtained parameters and the characteristics of the EMRWG. A 2-post filter with a center frequency of 4.5 GHz and a bandwidth of 170 MHz was designed using a WR-90 waveguide, and the simulation results by using the HFSS and CST, equivalent circuit model were in good agreement.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.430-432
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• 1988

Radiation admittance of the rectangular microstrip antenna is calculated by using equivalent ${\pi}$-network parameters of the slit in the wall of the parallel plate waveguide filled with homogeneous dielectric. Using equivalent transmission line model, return loss is calculated and compared with experimental result. Calculated values for the return loss show good agreement with experimental values.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.398-400
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• 1987

Using the transmission line model, we have developed a formalism which is fairly accurate and convenient for analyzing the dispersion characteristics of rectangular dielectric waveguides for integrated optics. The fields in open half space regions are expressed as a Fourier integral form. Including all the TE and TM polarized discrete modes in slab waveguide region, our calculation shows that the discrepancies between the previous vectorial wave analysis using one discrete mode and the brute-force numerical analysis for the rectangular dielectric waveguides can be fully reduced with this method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.12 s.91
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• pp.1123-1130
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• 2004

In this paper, a technique is presented f3r the design of a structurally simple narrow-band orthomode transducer (OMT) operating at 12/14 GHz frequency bands. The proposed OMT has such a structure that a horizontally polarized wave incident on the circular waveguide of the common port is directed to the rectangular waveguide of the straight port, while the vertically polarized wave is directed to the rectangular waveguide of the side port. Firstly methods are developed f3r designing individual parts of the OMT based on the waveguide theory and the theory of impedance matching. Secondly based on developed methods the whole OMT structure is designed using a commercial electromagnetic field analysis software. The validity of the proposed design technique is confirmed by fabricating and testing the designed OMT.