• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.5
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• pp.491-503
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• 2014

In this paper, a $TM_{31}$ higher order mode half circular-ring microstrip antenna with monopole-like radiation characteristic for on-body communication is proposed. By using shorting vias, $TM_{31}$ resonance mode was excited, while achieving compact low-profile antenna with monopole-like radiation characteristics. To overcome the narrow bandwidth of a patch antenna, a C-shape half ring patch with shorting vias having $TM_{31}$ mode is closely located around a half circular patch. For size reduction, half mode is adopted. The proposed antenna has the overall dimensions of $0.25{\lambda}_0{\times}0.46{\lambda}_0{\times}0.025{\lambda}_0$ at the industrial, scientific, and medical(ISM) 2.45 GHz band(2.4~2.485 GHz) and the 10-dB return loss is 4.24 % ranging from 2.38 to 2.49 GHz. To verify body effect, two-thirds muscle equivalent semi solid phantom was fabricated and used to measure the antenna performance. A communication link is analysed to investigate the effect of human-body movements and antenna locations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.3
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• pp.440-444
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• 2002

A microstrip patch antenna with circular polarization based on the Sierpinski fractal geometry is proposed. The Sierpinski fractal is composed of 3 equilaterial triangular patch and is easy to produce a circular polarization by sequentially rotation techniques. The characteristics of a 1x3 antenna array from Sierpinski geometry are investigated, i.e. port isolation and AR(axial Ratio).

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.132-136
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• 2017

In this paper, expanded lowest operating frequency by adopting circular slot on ground of balun and balance improved balance performances by stacking dielectric layer balun is proposed. Bandwidth of proposed balun is 1~7 GHz, and electrical length is $0.05{\lambda}$ at 1 GHz. In order to check performances of the proposed balun, simple dipole is integrated with the balun and radiation pattern of dipole is measured.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.119-123
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• 2000

This paper described a design for microstrip antenna with EMC cross dipole for circular polarization. To realize the wide bandwidth and circular polarization, the elertromagnetic-coupled cross dipole are used. The calculated axial ratio is about 0.1 dB in the main bean direction at 12 GHz and the circular polarization is realized.

• Journal of information and communication convergence engineering
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• v.13 no.3
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• pp.159-166
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• 2015

In this paper, a novel design for a triple-band coplanar waveguide (CPW)-fed monopole antenna for WLAN/WiMAX operations is proposed. The proposed antenna is printed on an FR4 substrate with an area of 22.0 mm × 30.0 mm, a thickness of 1.0 mm, and a relative permittivity of 4.4. The effects of various parameters of the proposed for triple band operation is investigated. Two half circular rings and a microstrip feed line are fabricated on the substrate to achieve triple band operation and good impedance matching. Prototypes of the proposed antenna have been fabricated and tested. Experiment results reveal that the measured return loss exhibits an acceptable agreement with the simulated return loss and satisfies the impedance bandwidth requirement of -10 dB, while simultaneously covering the WLAN and WiMAX bands. In addition, the proposed antenna shows good radiation characteristics and gains in the three operating bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.12
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• pp.1316-1324
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• 2009

In this paper, cross-aperture coupled microstrip circular polarization antenna is proposed for 5.8 GHz WLAN(Wireless Local Area Network). A single antenna consists of square patch and slots are located in series feed line with $\lambda_g$/4 phase different which make current direction maximum and minimum repeatedly to generate RHCP(Right Handed Circularly Polarization). We are proposed new structure that removed the section which intersected at a right angle and were composed to four separated slots. The proposed cross slots reduce back lobe of radiation pattern and improve antenna gain. Impedance bandwidth of the manufactured $2\times2$ array antenna is from 5.67 to 5.95 GHz and the maximum radiation gain is 10.59 dBi.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.441-444
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• 2008

This paper describes the development of a circularly polarized microstrip antenna, as a part of the Circularly Polarized Synthetic Aperture Radar (CP-SAR) sensor which is currently under developed at the Microwave Remote Sensing Laboratory (MRSL) in Chiba University. CP-SAR is a new type of sensor developed for the purpose of remote sensing. With this sensor, lower-noise data/image will be obtained due to the absence of depolarization problems from propagation encounter in linearly polarized synthetic aperture radar. As well the data/images obtained will be investigated as the Axial Ratio Image (ARI), which is a new data that hopefully will reveal unique various backscattering characteristics. The sensor will be mounted on an Unmanned Aerial Vehicle (UAV) which will be aimed for fundamental research and applications. The microstrip antenna works in the frequency of 1.27 GHz (L-Band). The microstrip antenna utilized the proximity-coupled method of feeding. Initially, the optimization process of the single patch antenna design involving modifying the microstrip line feed to yield a high gain (above 5 dBi) and low return loss (below -10 dB). A minimum of 10 MHz bandwidth is targeted at below 3 dB of Axial Ratio for the circularly polarized antenna. A planar array from the single patch is formed next. Consideration for the array design is the beam radiation pattern in the azimuth and elevation plane which is specified based on the electrical and mechanical constraints of the UAV CP-SAR system. This research will contribute in the field of radar for remote sensing technology. The potential application is for landcover, disaster monitoring, snow cover, and oceanography mapping.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.1
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• pp.1-8
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• 2011

In this paper, dual-feed circularly polarized microstrip patch antenna for GPS L1, GPS L2, GLONASS L1 signal was fabricated by using stacked patch. It was fed by dual coaxial probe on the patch at 50ohm impedance, and was simulated to resonate at GPS L1, GPS L2, GLONASS L1. To realize characteristics of right hand circular polarization using dual-feed stacked patch antenna and hybrid coupler for $90^{\circ}$ phase difference. Output of hybrid coupler was contacted input of Low Noise Amplifier(LNA). The LNA using dual band pass filter was designed and fabricated. The measured results of the implemented antenna is VSWR < 1.5 : 1 and the gain of 32dB(Zenith) over at GPS L1, L2, GLONASS L1.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.50-57
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• 2001

This paper describes a design for the circularly polarized microstrip EMC cross dipole array antenna with the wide bandwidth. To realize the characteristics of wide bandwidth and circular polarization, the electromagnetic-coupled cross dipole element is proposed. The optimum design parameters of a circularly polarized EMC cross dipole element are calculated by the FDTD and the Ensemble. To obtain the uniform aperture illumination of electric field in an array, offset technique that the cross dipole elements are alternatively arranged on center of the microstrip feed line is adopted. In 20-element array design, the calculated axial ratio and gain are about 0.1dB and 9.9 dBi at 12 GHz, respectively, The frequency characteristics of a fabricated 20-element array antenna are measured. The calculated results agree well with the measured ones.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.542-545
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• 2003

An microstrip array antenna is designed based on the Sierpinski equilateral triangular patch. The Sierpinski geometry is composed of 3 equilateral triangular patch and is easy to generate a circular polarization by sequential rotation array techniques. This 1${\times}$3 Sierpinski equilateral triangular patch antenna is extended to 8${\times}$8 array antenna for satellite broadcasting receptions.