• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.245-252
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• 2018

In this paper, the dual band circular polarization patch antenna was designed by using band rejection characteristics of CSRR structure for geostationary satellites. A quadrangular CSRR structure was etched on the ground at the rear of the patch antenna's feed to obtain band rejection characteristics in between the receiving frequency band(1525~1559MHz) and transmission band(1626.5~1660.5MHz), and the corner of the patch antenna was truncated to enable circular polarization. It was confirmed that the resonant frequency of the patch antenna differs according to the size anc location of the CSRR and cirular polarization characteristics with simulation and measurement results. Measurement results shows the gain of about 0.2dB and 1.5dB in the TX and RX band.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2270-2277
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• 2016

In modern society, creation and distribution of multimedia contents is being actively conducted. These multimedia information have come out the enormous amount daily, the amount of data is also large enough it can't be compared with past text information. Since it has been increased for a need of the method to efficiently store multimedia information and to easily search the information, various methods associated therewith have been actively studied. In particular, image search methods for finding what you want from the video database or multiple sequential images, have attracted attention as a new field of image processing. Image retrieval method to be implemented in this paper, utilizes the attribute of corner patches based on the corner points of the object, for providing a new method of efficient and robust image search. After detecting the edge of the object within the image, the straight lines using a Hough transformation is extracted. A corner patches is formed by defining the extracted intersection of the straight line as a corner point. After configuring the feature vectors with patches rearranged, the similarity between images in the database is measured. Finally, for an accurate comparison between the proposed algorithm and existing algorithms, the recall precision rate, which has been widely used in content-based image retrieval was used to measure the performance evaluation. For the image used in the experiment, it was confirmed that the image is detected more accurately in the proposed method than the conventional image retrieval methods.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.283-288
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• 2011

This paper have proposed an object retrieval using the corners area variability based on correlogram. The proposed algorithm is processed as follows. First, the corner points of the object in an image are extracted and then the feature vectors are obtained. It are rearranged according to the number dimension and consist of sequence vectors. And the similarity based on the maximum of sequence vectors is measured. The proposed technique is invariant to the rotation or the transfer of the objects and more efficient in case that the objects present simple structure. In simulation that use Wang's database, the method presents that the recall property is improved by 0.03% and more than the standard corner patch histogram.

• Structural Engineering and Mechanics
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• v.4 no.5
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• pp.569-586
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• 1996

A new three-dimensional 8-node solid element with rotational degrees of freedom is presented. The proposed element is established by adding rotational degrees of freedom to the basic 8-node solid element. Thus the element has three translations and three rotational degrees of freedom per node. The corner rotations are introduced by transforming the hierarchical mid-edge displacements which are parabolic shape along an edge. The derivation of the element is based on the mixed variational principles in which the rotations are introduced as independent variables. Several types of non-conforming modes are selectively added to the displacement fields to obtain a series of improved elements. The resulting elements do not have the spurious zero energy modes and Poisson's ratio locking and pass patch test. Numerical examples show that presented non-conforming solid elements with rotational degrees of freedom show good performance even in the highly distorted meshes.

• ETRI Journal
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• v.27 no.3
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• pp.250-256
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• 2005

A novel planar polarization-agile microstrip subarray is proposed and its performance assessed by a thorough numerical investigation. The subarray consists of five square patches with a central element, directly coupled to a pair of microstrip feed lines by a cross-shaped aperture, which spreads the power outwards to the other patches through a network of suitable connections. By properly exciting the antenna at its input ports, any kind of polarization of the radiated field can be accomplished with fairly low cross-polarization levels. Moreover, since only two feed lines are required to drive the whole subarray, polarization agility is simply and attractively achieved by a single phase-shift circuit. The design concept is described and the results of the analyses and simulations performed by two completely independent full-wave approaches are presented and discussed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1208-1213
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• 2010

In this paper, a microstrip balun-BPF of slotted-square-patch type is proposed. The conventional balun-BPF has some drawbacks of narrow bandwidth and high insertion loss. In order to improve these weak points, we used a square patch in designing balun-BPF on which two slots intersecting perpendicularly and one corner-edge perturbation are adopted. This structure allows one of the most effective use of the patch space so that the insertion loss can be decreased. Changing the slot lengths is use to control the operating frequency and the bandwidth of the balun-BPF. A fabricated balun-BPF shows wide bandwidth of 300 MHz(12.7 %), small insertion loss of 0.56 dB, phase difference of $184^{\circ}{\pm}15^{\circ}$ and amplitude imbalances of within 1 dB between two output ports at 2.4 GHz band.

• Journal of IKEEE
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• v.17 no.2
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• pp.140-144
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• 2013

This paper presents the novel design of circular polarized Ka-band horn array antenna. The element antenna of the arrya is composed of two parts, microstrip patch and square horn, and the microstrip patch is fed by corner truncated microstrip patch for circular polarization. The patch antenna has the role of a feeder and polarizer of the horn, thus the whole size of the horn antennae can be considerably reduced. The $1{\times}8$ horn array was designed and fabricated by the spacing of $0.9{\lambda}_0$ among the element horn. The element horn has typical gain of 8dBi and axial-ratio bandwidth of 4.9% at 3dB, and the minimum gain and axial-ratio bandwithd of the array is 14dBi and 8.2%.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.2 s.302
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• pp.11-18
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• 2005

To detect vehicles in image, first the image is transformed with the steerable pyramid which has independent directions and levels. Feature vectors are the collection of filter responses at different scales of a steerable image pyramid. For the detection of vehicles in image, feature vectors in feature points of the vehicle image is used. First the feature points are selected with the grid points in vehicle image that are evenly spaced, and second, the feature points are comer points which m selected by human, and last the feature points are corner Points which are selected in grid points. Next the feature vectors of the model vehicle image we compared the patch of the test images, and if the distance of the model and the patch of the test images is lower than the predefined threshold, the input patch is decided to a vehicle. In experiment, the total 11,191 vehicle images are captured at day(10,576) and night(624) in the two local roads. And the $92.0\%$ at day and $87.3\%$ at night detection rate is achieved.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.769-777
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• 2010

In this paper, a switchable circularly polarized microstrip patch antenna using PIN diodes and corner slots on ground plane is proposed at 2.4 GHz. The proposed antenna has a square microstrip patch and ground plane that consists of two pair of slots and PIN diodes. The electrical lengths of the slots are adjusted by using the switching characteristic of the PIN diode, so the polarization of the proposed antenna can be switchable between linear, left-handed(LH) and right-handed(RH). By separating the ground plane for the DC bias, the size reduction effect is also obtained. When the proposed antenna is operated as linear polarization, the return loss and impedance bandwidth are 15 dB, 59 MHz, and when operated as LH and RH polarization, the minimum axial ratio and 3-dB axial ratio bandwidth are 1.17 dB, 1.67 dB, 28 MHz, and 32 MHz, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.411-417
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• 2008

This paper presents the miniaturization of circularly polarized microstrip patch antenna for UHF-band RFID portable reader. The proposed antenna has a group of four I-slots on a conventional corner-truncated square microstrip patch and it is shown that the antenna size is reduced compared to the antenna without I-slots. A 76 mm by 76 mm small antenna with four I-slots is fabricated with 6.4 mm thick FR4 substrate and its 10 dB return loss bandwidth, the gain and the axial ratio are measured to be $938{\sim}975\;MHz$, $-0.88{\sim}-2\;dBi$, and $3.27{\sim}13.21\;dB$ within the 10 dB return loss bandwidth, respectively.