• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1362-1369
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• 2018

A method aimed at improving the beam-wave interaction efficiency by changing the coupling slot configuration has been proposed in the study of extended interaction oscillators (EIOs). The dispersion characteristics, coupling coefficient and interaction impedance of the high-frequency structure based on different types of coupling slots have been investigated. Four types of coupled cavity structures with different layouts of the coupling slots have been compared to improve the beam-wave interaction efficiency, so as to analyze the beam-wave interaction and practical applications. In order to determine the improvement of the coupling slot to a coupled cavity circuit in an EIO, we designed four nine-gap EIOs based on the coupled cavity structure with different coupling slot configurations. With different operating frequencies and voltages takes into consideration, beam voltages from 27 to 33 kV have been simulated to achieve the best beam-wave interaction efficiency so that the EIOs are able to work in the $2{\pi}$ mode. The influence of the Rb and the ds on the output power is also taken into consideration. The Rb is the radius of the electron beam, and the ds is the width of the coupling slot. The simulation results indicate that a single-slot-type EIO has the best beam-wave interaction efficiency. Its maximum output power is 2.8 kW and the efficiency is 18% when the operating voltage is 31 kV and electric current is 0.5 A. The output powers of these four EIOs that were designed for comparison are not less than 1.7 kW. The improved coupling-slot configurations enables the extended interaction oscillator to meet the different engineering requirements better.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.2
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• pp.495-504
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• 1996

In this paper, series-fed mirostrip array anteenas with coupling-slots are prposed and their operating characteristics are analyzed based on analyzed based on analytical and experimental results. An accurate analysis method for the slot-coupled feed structure is based on using both circuit coupling between anteenas and full-wave analysis which use travling wave mode and non-traveling wave mode on feed line. The basis functions that used for the numerical analysis bas been determined depending upon the accuracy, convergence properties of the solution, and the computation time:The patch uses 3 EB mode, the slot uses 1PWS mode, and feeders use 5 PWS mode. Series-fed array antennas have been designed, built, and tested in a standing-wave configuration. Using the results of the full-wave analysis, the chebyshev array antennas consisting of 8 elements are designed and fabricated changing the amount excited to each array element by adjusting slot length and by the slot position relative to the feeder. Experiment results show that the series-fed array antenna designed by adjusting the slot position relative to the feeder is superior to that designed by slot length.

• Journal of Korea Society of Industrial Information Systems
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• v.6 no.4
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• pp.6-11
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• 2001

In this paper, the aperture-coupled U-slot microstrip patch antenna is studied for the bandwidth improvement. The aperture is used as a mechanism for coupling the radiating element to the microstrip feedline, and the aperture-coupled configuration provides the advantage of isolating spurious feed radiation by the use of common ground plane. Experimental results such as return loss, VSWR, radiation pattern and gain measurements are presented on the aperture-coupled U-slot microstrip patch antenna. The impedance bandwidth (VSWR≤2) of the antenna is 6.4% centered at 2.35GHz, and the average gain is 5.3 dBi.

• ETRI Journal
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• v.33 no.5
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• pp.802-805
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• 2011

This letter presents a K-band polarization reconfigurable antenna integrated with a silicon radio frequency MEMS switch into the form of a compact package. The proposed antenna can change its state from linear polarization (LP) to circular polarization (CP) by actuating the MEMS switch, which controls the configuration of the coupling ring slot. Low-loss quartz is used for a radiating patch substrate and at the same time for a packaging lid by stacking it onto the MEMS substrate, which can increase the system integrity. The fabricated antenna shows broadband impedance matching and exhibits high axial ratios better than 15 dB in the LP and small axial ratios in the CP, with a minimum value of 0.002 dB at 20.8 GHz in the K-band.