• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.2
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• pp.156-163
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• 2014

In this paper, a compact circularly polarized metamaterial patch antenna using cross aperture-coupled feed is proposed. The CP antenna utilizes the -1 mode that is induced by the composit right-left handed(CRLH) transmission line. Since the -1 mode has the same properties with the $TM_{010}$ mode of the conventional patch antenna, the circular polarization(CP) can be realized. If two orthogonal modes are excited with $90^{\circ}$ phase difference, the CP property can be obtained. In order to obtain two orthogonal modes and $90^{\circ}$ phase difference, 4 mushroom structures having the shape of square are employed. The width and length of the cross aperture are optimized through the design algorithm. The fabricated antenna is based on RT/duroid5880 substrate and the total area of the 4 mushroom is $0.25{\lambda}_0{\times}0.25{\lambda}_0$. The center frequency of the LHCP(Left-Handed Circular Polarization) antenna is measured as 1.622 GHz and circular polarization bandwidth(3 dB) is measured as 3 MHz. The center frequency of the RHCP(Right-Handed Circular Polarization) antenna is measured as 1.609 GHz and circular polarization bandwidth (3 dB) is measured as 3 MHz, respectively. The measured radiation efficiency of LHCP antenna is 61.1 % and the measured radiation efficiency of RHCP antenna is 54.5 %.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1294-1302
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• 2008

A design approach for a radiation element of dual polarization, which can be implemented in the waveguide structure, is proposed. For minimization of the radiating element, the ridged waveguide type is used and for dual polarization, the microstrip type of printed dipole structure is additionally installed inside the waveguide. In order to validate the design approach, $1{\times}4$ array antenna is fabricated and its performances such as return loss, co-polarization coupling between adjacent channels, and radiation patterns are investigated. Theory and experiment are observed to be in good agreement. The radiating structure is thought to be a useful one in an application to the phased array antenna system, in particular, requiring dual polarization characteristics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.748-754
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• 2000

A novel single feed wide band CP stacked microstrip antenna using crossed slots has been designed, fabricated and measured. For the single rediating element the designed 10dB return loss bandwidth is 34.5%99.45~13.54 GHz), 3dB axial ratio bandwidth is 18.7%(11.17~13.39GHz), and 6 dB gain bandwidth is 29%(10.21~13.64GHz). For the 2$\times$2 array designed using a sequential rotation method, the 10dB return loss bandwidth is 35.9%(9.69~13.94GHz), 3dB axial ratio bandwidth is 34.6GHz (9.93~14.03GHz), and 6dB gain bandwidth is 27.4%(10.35~13.6GHz). For the fabricated 8$\times$8 array antenna, the 10dB return loss bandwidth is 27.3%(10.17~13.41GHz), 3dB axial ratio bandwidth is 27.9GHz(10.1~13.4GHz), and the radiation pattern is good agreement with theory. This antenna can be used for broadband applications for communications or broadcasting in Ku band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.216-219
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• 2016

In this paper, the SIW(Substrate Integrated Waveguide)-based feeding antenna for the application of SDR(Software Defined Radar) is designed and manufactured. It is usually well-known that SIWs are easily integrated on PCB and have low transmission loss toward high powered input signal. Also, it is recommended that SIWs are strongly immunized to Electromagnetic Interferences(EMI). In particular, the manufactured antennas are loaded on the USRP(Universal Software Radio Peripheral) platform and employed to detect target RCS as an experiment in this paper. The operating frequency of the proposed antenna is in ISM(Industrial, Scientific and Medical) band(2.4~2.48 GHz) and the measured gain is over 8 dBi at 2.44 GHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.4
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• pp.894-900
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• 2004

There are many types of circularly polarized(CP) microstrip antenna elements, which are used as a good unit radiator. Since an advantage of CP antenna is no strict alignment requirements between Rx and Tx system, the printed antennas with circular polarization are very often used in numerous satellite and mobile radio systems. In order to realize the broad bandwidth of 3 dB axial ratio and impedance of CP microstrip antenna, complex feed structure and tri-plate patch element have been researched. This paper describes a design of wideband microstrip cross slot array antennas with circular polarization. The proposed antenna is composed of an open-ended microstrip feed line as a feeder and a cross slot as a radiator for circular polarization. To realize the wide bandwidth, tri-plate structure are considered and cross slot is electromagnetically coupled with feed line. Optimum parameters of 1-element cross slot antenna are analyzed and designed by method of moments. These parameters are also applied to may antennas design considered the mutual coupling between radiating elements. Right hand circular polarization(RHCP) and left hand circular polarization(LHCP) of the proposed antenna are easily controlled by asymmetrical cross slot structure and slot position. In 1-element and 15-element cross slot array antenna, the good axial ratio of 1 dB below and the broad bandwidth characteristics of antenna are obtained.

• Journal of electromagnetic engineering and science
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• v.4 no.3
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• pp.128-136
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• 2004

In this paper,. with the aim of achieving the expected performance improvement for a polarization diversity system, we analyzed two-branch polarization diversity at the receiving end of a mobile link which a transmitter emits circularly polarized wave. In this analysis, to calculate the correlation coefficient considered by XPD(cross polarization discrimination) between the two received signals, a simple theoretical model of circular polarization diversity is adopted. From the analysis results, it is clearly seen that the correlation coefficient of circular polarization diversity evaluated by the XPD is less than that of conventional linear polarization diversity. And also, we designed and implemented a circular polarization diversity system with micro-strip antenna. By using the circular polarization diversity system, we analyzed the measured data in indoor NLOS(Non-Line-Of-Sight) environments. From this analysis results, it is also clearly seen that the diversity effect of circular polarization diversity system shows better performance compared to the conventional linear diversity system by about 3 dB high.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.228-235
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• 2011

In this paper, we propose a $4{\times}8$ SIW(Substrate Integrated Waveguide) slot array antenna for dual-polarized phased array system. The basic part of the array is a subarray comprising an vertical-polarization and horizontal-polarization. A vertical-polarization slotted SIW single-polarization linear array. Using SIW, A vertical polarization linear array consists of 8 uniform longitudinal slots and 4-way SIW feeding network. Using HMSIW, horizontal-polarization linear array consists of 8 slots and 4-way SIW feeding network.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.1
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• pp.36-41
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• 2018

This paper presents an implementation of a millimeter-wave(W band) multiflare-angle horn antenna. The proposed antenna is a multimode dual-polarized square horn having equal E- and H-plane beamwidths and consists of a multimode generating section, a four-square-waveguide exciter, orthomode transducers, and power combiners for the sum pattern formation. The antenna structure has been designed to allow for easy fabrication and the designed antenna has been fabricated to a precision of ${\pm}0.02mm$ by layer-by-layer machining and diffusion bonding. The input reflection coefficient and the radiation pattern of the fabricated antenna have been measured using a network analyzer and a far-field test facility. Measurements show that the proposed antenna has 17.7~18.3 dBi gain, $25.2{\sim}28.5^{\circ}$ beamwidth, and an input VSWR between 1.02~1.75, within ${\pm}0.5GHz$ from the center frequency.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.3
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• pp.199-205
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• 2017

In a small cell base station used in densely populated areas, a dual polarized multiple antenna(MIMO) is mainly used to increase the cell capacity. This paper demonstrates a dual-polarization antenna with high cross-polarization discrimination(XPD) that can improve the capacity of a small cell using a dual polarization multiple antenna (MIMO). By using the symmetric structure and differential feeding, high XPD in all directions is achieved. In addition, a very similar radiation pattern is observed between each polarization. Because of high XPD and similar radiation pattern in all directions, proposed antenna is well adopted for small-cell multiple-input multiple-output(MIMO) system. Experimental results shows that the proposed antenna has a bandwidth of 180 MHz (2.51~2.7 GHz), a maximum gain of 4.5 dBi (3.5~4.5 dBi), and a half-power beam width of 85 degrees. In addition, average XPD of 26.4 dB in all directions, more than 13.8 dB increase than previous dual-polarization antennas which use single emitter by using different feeding or selectively use polarization through switching.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.3
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• pp.32-40
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• 1991

A modified transmission line model is proposed for input impedance analysis of a square microstip antenna with single-circularly-polarized. Alog-periodic arrangement with microstrip antenna (LPMA) which consists of 3 resonant element ($3\times1$) is designed for broadband operation ranging from 11.2 GHz to 12.4 GHz, based on this pro- posed model from transmission line model. Aplanar array ($3\times4$array), in which 4sets of the above LPMA are in the same plane, is fabricated for high gain X-band satellite communication antennas. The optimum spacing between each LPMA is determined using computer simulation for the minimum bariation of far field pattern and null. This $3\times4$array has a measured values of gain greater than 8dBi, VSWR les then 2.3, and bandwidth greater than 7% respectively.