• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2001.11a
• /
• pp.198-201
• /
• 2001

L자형 루프를 이용하여 주파수대역이 6-18 GHz인 동축-이중릿지도파관 변환기를 상용 소프트웨어인 HFSS를 이용하여 설계한 후 제작하였다. L자형 루프는 동축-구형도파관 변환기에 이미 이용되고 있는 구조로써, 이를 동축-이중릿지도파관 변환기에 적용한 것이다. 제작 후 측정결과 대역폭이 6-18 GHz로 3:1 이상을 만족하며, 최대 삽입손실이 -1.52 dB 이었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.7 no.3
• /
• pp.246-253
• /
• 1996

In this paper, a problem that occurred in the telegraphist equation established by mode conversion method is solved as analysis tapered transmission line is applied to a waveguide taper. After comparing and analyzing the taper function with variant properties, we select on of taper functions not only that is easily designed but also that have good properties. And then we propose the applicant method to design the waveguide taper and deal with the design of mode transducer between rectangular waveguide and circular waveguide. The measured results of scattering coefficients for the mode transducer fabricated with designed data are agreed well with the theoretical results and the validity of the proposed design and analysis method has been confirmed.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.10 no.5
• /
• pp.79-86
• /
• 2011

In this paper, a S-band coaxial waveguide-based spatial combiner is proposed. The proposed combiner consists of coaxial waveguide, impedance transformer, and finline-to-microstrip transformer. The coaxial waveguide is used as the host of the combining circuits for higher output power and better uniformity by equally distributing the input power to each element. The finline-to-microstrip transformer is designed by using antipodal antenna, and obtained low reflection coefficient by applying the small reflection theorem. The measurement results show the coaxial waveguide combiner has a maximum combining efficiency of 95%.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.49 no.4
• /
• pp.47-52
• /
• 2012

We have designed the waveguide to microstrip transition using a probe structure for the center frequency of 200 GHz transceiver. The waveguide to microstrip transition is composed of probe, taper and microstrip transmission line. For design of the transition, we simulated the lengths and width of the probe and the taper to optimize the center frequency and the bandwidth using HFSS simulation tool from Ansoft. The transition is designed back-to-back structure. From the simulation results, the transition exhibits that insertion loss is below - 0.81 dB and the return loss less than -10 dB in range of 186 ~ 210 GHz.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.10
• /
• pp.65-70
• /
• 2008

We design and fabricate the 94 GHz Coplanar waveguide(CPW)-to-rectangular waveguide transition that is transmits signal smoothly between the CPW, which is a popular transmission line of the planar circuits, and rectangular waveguide for the 94 GHz transceiver system. The proposed transition composed of the unilateral fin-line taper and open type CPW-to-slot-line transition is based on the hard and inflexible sapphire for the flip-chip bonding of the planar MMICs using conventional MMIC technology. We optimize a single section transition to achieve low loss by using an EM field solver of Ansoft's HFSS and fabricate the back- to-back transition that is measured by Anritsu ME7808A Vector Network Analyzer in a frequency range of $85{\sim}105$ GHz. From the measurement and do-embedding CPW with 3 mm length, an insertion and return loss of a single-section transition are 1.7 dB and more an 25 than at 94 GHz, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.5C
• /
• pp.506-511
• /
• 2002

In this paper, waveguide-based power combiner using conventional slotline-to-microstrip transition was proposed at Ka-band. The proposed 2-way and 4-way power combiner consist of waveguide-to-slotline transition, two or four slotline-to-microstrip transitions, and impedance matching networks. Their structures were simulated and optimized by 3-D FEM simulation. The 2-way power combiner showed a very low back-to-back insertion loss of 1.0 dB and return loss better than 15 dB from 25.7 GHz to 29.8 GHz except the resonant frequency. The 2-way power combining approach was extended to 4-way power combining using slotline tee junction. The 4-way power combiner showed the similar performance to that of 2-way power combiner with 2 GHz smaller bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.23 no.7
• /
• pp.1770-1776
• /
• 1998

This paper presents a waveguide-to-mircostrip transition at Ka-band using antipodal finlines. Critical design parameters were identified with the help of theoretical analysis. Experimental optimization was performed together with 3-D FEM analysis in an effort to find optimum dimensions of the transition. In addition to the conventional antipodal finline transition, a new dielectric impedance transformer was introduced to further reduce the insertion loss. Optimized waveguide-to-microstrip transition showed an insertion loss of 0.3~0.4dB/transition at Ka-band. This transition provides superior reproducibility and better performance than conventional coaxcable-to-microstrip transition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.569-571
• /
• 2007

In this paper, hem antenna composed of rectangular hern, circular polarizer and straight-type mode convertor is designed and fabricated. The circular polarizer is designed as a dielectric type having broadband characteristic, and it is inserted into the rectangular hem with $45^{\circ}$ inclination. The straight-type mode convertor has a terrace-type structure in order to convert the TEM mode signal of coaxial cable to the TE mode of rectangular waveguide, and this structure minimizes conversion loss. Fabricated hem antenna operates at $30.085\sim30.885GHz$ and has VSWR < 1.5, Axial ratio < 1.0dB and antenna gain of $6.7\sim7.0dBi$ in the band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.7 no.3
• /
• pp.254-262
• /
• 1996

In this paper, we present a polarizer that consists of three step rotary detents which can selectively convert linear polarzation into circular polarization and vice versa. For the design of the polarizer, the transmission line theory is applied to design the wa- veguide mode transducer for the modes to be smothly converted in waveguides, and a dielectric plate is inserted in circular waveguide for the conversion of a polarized wave with the angle of an inserted dielectric plate. Also, we simulated to obtain the optimum values of the transmission and the reflection coefficient characteristics at input and output port, and proved the propriety of the theory from the knowledge of measuring the constructed polarizer with the designed data.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.4
• /
• pp.77-82
• /
• 2017

As frequencies increase to the millimeter wave bands the cross sections of wave guides become smaller than a few millimeters, which cause sapatial problems in realization of spatial combining power amplifiers. In this paper we intented to overcome the problem by widening the width of wave guides using horn antenna principles. We designed a widened rectangular wave guide for using in spatial combining power amplifier in 60GHz ISM band(57-64GHz), and we installed Antipodal transition in the widened wave guide, and then we characterized it as a spatial combining power amplifier. For the compatibility of WR15 standard wave guide, we widened the width of WR15 to 7mm using principle of H-plane sectoral horn antenna and then installed 3 slots of back to back Antipodal transition. The designed spatial combining power amplifier showed good characteristics of return loss less than -22.4dB and insertion loss less than 0.53dB. However, as widening the width of the wave guide, additional modes such as $TE_{20}$, $TE_{30}$ in addition to $TE_{10}$ were accurred in the bandwidth of WR15, which restricted the bandwidth and widening of the width of the wave guide.