• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.319-323
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• 2000

A method for miniaturization of microstrip patch antenna without degrading its radiation characteristics is investigated. The ring geometry introduces additional parameters to the antenna that can be used to control its resonance frequency and bandwidth. For a single square ring increasing the size of patch decreases the resonance frequency and bandwidth. To match the antenna to a transmission line and also enhance its bandwidth. the square ring patch is stacked by a square ring patch. The computed results are compared with experiment and good agreement is obtained.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.8
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• pp.448-454
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• 2004

In this paper, circular polarized antennas of Tx 30GHz and Rx 20GHz are implemented in LTCC process. Tx antenna has a circular patch structure and Rx antenna has a ring patch structure. The feeding line of Tx antenna is placed in the center hole of Rx ring patch antenna which is printed under Tx circular patch antenna layer. It makes antenna size smaller. Tx antenna's return loss in under -l0dB level from 30GHz to 31GHz and Rx antenna is under -10 dB from 20GHz to 21GHz. The isolation between two antennas is less than -20dB. Axial ratio is less than 3dB thoughout each band.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.2 no.4
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• pp.28-41
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• 2003

A micros-strip ring patch antenna with ultra wide band characteristics is presented. The proposed antenna is designed by a modified form of the annular ring patch antenna with modified microstrip feedline. The designed antenna gives 5.6GHz bandwidth with regular radiation pattern from 4.4GHz to 12.0GHz for -10dE return loss or VSWR of less than 2.0 in simulation, which is also excellently agreed with the measured data.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.378-381
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• 2014

A new pathogen was isolated from zoysiagrass-planted park of Jeju island in 2014. Symptoms appeared a type of irregular patches occurring brownish leaf blight, followed by stem and crown rot. The symptom was very similar to that of large patch caused by Rhizoctonia solani, a well-known devastating zoysiagrass disease. The isolate showed thin orange-colored mycelia and screlotia were formed on the medium based on cultural characteristics. The causal agent of the disease was finally identified as Waitea circinata by analysis of ribosomal DNA. On the inoculation test, Waitea circinatae showed strong pathogenicity to the zoysiagrass. The mycelia were obviously observed in the inoculated tissues. This is the first report of Waitea ring patch caused by Waitea circinata on zoysiagrass.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.5
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• pp.435-441
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• 1989

The three rectangular microstrip patch antenna of Resonant length, lambda/2 or , between two slot is designed by using the ring feed line, and the radiation pattern characteristic is showen. In case of the antenna of resonant length lambda/2 the radation pattern is shown at each antenna element, in the antenna of resonant length it is shown among patch antenna element.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.998-1009
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• 1999

In this paper, a microstrip aperture-patch antenna and a microstrip ring antenna, which have single microstrip line feeding systems for the circular polarization, are designed, and experimental results are presented at X-band. The microstrip aperture-patch antenna is characterized by its wide operating frequency range, and the microstrip ring antenna is suitable for a basic radiator in the large array antenna due to its small size. Several design parameters for these antennas are considered and analyzed to improve antenna characteristics such as VSWR bandwidth and axial ratio. Initially, the sizes of the aperture and ring radiator are determined on a basis of the cavity model, then shapes of the patch within the aperture and the inner stub of the ring are optimized using Ensemble software. Measurement results show that the aperture-patch antenna has 25% of VSWR bandwidth and 1.2dB of axial ratio at the boresight, and the ring antenna has 6.7% of VSWR bandwidth and 1.6dB of axial ratio at the boresight.

• Journal of electromagnetic engineering and science
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• v.12 no.4
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• pp.247-253
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• 2012

This study presents a new, simple method for improving the front-to-back (F/B) ratio of a microstrip patch antenna. The back radiation of the microstrip patch antenna is reduced by removing some metallic parts around the ground plane and placing a new soft-surface configuration, consisting of an array of stand-up split-ring resonators on a bare dielectric substrate near the two ground plane edges. Compared to the F/B ratio of a conventional microstrip patch antenna with a full ground plane of the same size, our proposed microstrip patch antenna experimentally achieves an improved F/B ratio of 9.6 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.4
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• pp.351-356
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• 2009

A dual-mode annular ring antenna for both global positioning system(GPS) and satellite digital multimedia broad-casting(DMB) is designed. The proposed antenna consists of a coupling feed line and four slots on the annular ring patch. The gap between the feed line and the annular ring patch is used for an input impedance matching, and the slot length is used for adjusting the resonant frequency of the $TM_{21}$ mode at the DMB frequency. The antenna was fabricated and measured. The experimental results show that the antenna resonants at the GPS and DMB frequencies with suitable bandwidths, and had a broadside radiation pattern at the GPS band and a conical beam radiation pattern at the DMB band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.143-152
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• 2001

A method for miniaturization of microstrip patch antenna without degrading its radiation characteristics is investigated in this paper. It involves perforating the patch to form a microstrip square-ring antenna, and it's BW enhancement is investigated numerically and experimentally. A ring geometry introduces additional parameters to the antenna, and those are used to control impedances, resonance frequencies, and bandwidths. For a single square ring antenna, an increase of the size of perforation increases its input impedance, decreases the resonance frequency, and bandwidths. But it affects little on directivity of the antenna. To match the antenna to a transmission line and also enhance its bandwidth, the ring is stacked by a square patch or another square ring. Also numerically simulated results by the IE3D, and experimental data are compared for proof.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.2
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• pp.143-151
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• 2010

In this paper, a novel rectangular patch antenna is proposed to have Zeroth Order Resonance(ZOR) generated based on the Metamaterial Complosite Right- and Left-Handed(CRLH) structure. Making the in-phase electric field over the entire antenna other than a half-wavelength as the fundamental resonance mode of a standard microstrip patch or its positive multiple, the metallic patch is suggested to be capacitively coupled with only one surrounding rectangular ring, different from the previous 1D ZOR antennas commonly having several metal cells in line. The performance of the proposed antenna is simulated by a 3D field solver that inputs the sizes of the physical structure corresponding to the equivalent circuit designed to have ZOR at 2.4 GHz. Consequently, the resonance frequency, the gain and the antenna efficiency are observed 2.4 GHz, 5 dB and 98%, respectively. Besides, the important property of the proposed antenna is addressed as the combination of the low profile as an advantage of microstrip patch antennas, and the omni-directional field pattern typical of monopole antennas.