• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2615-2618
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• 2009

Double rectangular patch with 4-bridges is investigated for solution of IEEE 802.11b/g (2.4 GHz) and 802.11a (5.5 GHz). Rectangular patch for 5.5 GHz frequency band is printed on the PCB substrate and connected to another rectangular patch for 2.4 GHz frequency band with 4-bridges to obtain dual band operation in an antenna element. 4-bridges can modify the desired frequency band from its original frequency band by changing its width. Gain of 2.4 GHz patch is 5 dBi and 5.5 GHz patch is 3.7 dBi at ${\theta}=0^{\circ}$.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.450-453
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• 2003

In this paper, the miniaturization of linear polarization microstrip patch antenna is studied by attached Irises near the square linear polarization microstrip patch antenna which are induced the increase of current path. Microstrip patch antenna having the Irises is designed and fabricated at the resonant frequency of 1.575 GHz. The result is like that the resonant length of patch is reduced 41.5 mm which correspond to 50.9 % of that of plane type(81.5mm). The return loss is -28.5 dBd and -10 dB bandwidth is 103 MHz( 6.5 %). And as the radiation pattern is broad through the size reduction of patch, the gain is 5.9 dBd and -3 dB beamwidth of E-plane is $111.9^{\circ}$.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1738-1745
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• 2015

Radiation characteristics of a probe-fed rectangular microstrip patch antenna printed on a finite grounded high permittivity substrate are investigated systematically for various square grounded dielectric substrate sizes with several thicknesses and dielectric constants by experiment and full wave simulation. The effect of the substrate size on the radiation characteristics of a rectangular patch antenna is mainly determined by the effective dielectric constant of surface waves on a grounded dielectric substrate. As the effective dielectric constant of surface waves increases, the substrate sizes for the maximum broadside gain and the required onset for a large magnitude of squint angle decrease, while the variations of the broadside gain, the front-to-back ratio, and the magnitude of squint angle versus the substrate size increase due to the increase of the power of the surface wave.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.461-466
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• 2004

In this paper, the novel patch antenna for polarization diversity using switching element is presented. The proposed antenna consists of the square patch with a pair of truncated corners and a microstrip-feed line with power divider. A switching microstrip-line feed works at schottky diode ON / OFF that is placed at $\lambda$/4 point from branch-off point of power divider. Polarization diversity has two types(LHCP. RHCP) as switching the schottky diodes. The measured 3 ㏈ axial ratio bandwidth for switching operation is about 2 %.

• ETRI Journal
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• v.32 no.3
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• pp.468-471
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• 2010

A compact square patch antenna with reconfigurable circular polarization (CP) at 2.4 GHz is proposed. Circular polarization is generated by an arc-shaped slot on the ground plane. In order to switch the CP orientation, the current flow direction of the patch is reconfigured via the PIN diodes mounted on the slot. As the slot and bias circuit are not placed on the patch side, the proposed antenna radiates a CP wave without alteration in the main beam direction. From the experimental results, the impedance and CP bandwidths of the proposed antenna have been demonstrated for up to 80 MHz and 25 MHz, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.10
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• pp.1731-1736
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• 2008

In this paper, singly fed circularly polarized nearly-square patch antenna for receiving S-DMB is presented. It used teflon substrate of relative dielectric constant ${\in}_{\gamma}=2.2$ and the sire is $40{\times}40{\times}15[mm]$. Experimental results of fabricated antenna show that input return loss and axial ratio are about 22MHz, 25MHz at the center resonant frequency, respectively. And fabricated LNA has gain of 27.5 [dB], NF of 1.27 [dB], input return loss of -15.4 [dB] and output return loss of -18.9 dB, respectively. Simulation results and experimental results are good agreements. This proposed antenna is well able to handheld gadgets for receiving S-DMB.

• Korean Journal of Computational Design and Engineering
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• v.2 no.2
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• pp.122-129
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• 1997

Ball rolling blending is a popular technique for blending between parametric surfaces. The ball rolling blend surface is conceptually a trajectory of a ball rolling between two base sufaces. It is constructed by sweeping a circular arc along a ball contact curve pair. Since a ball rolling blend surfaces does not have a polynomial form like a Bezier surface patch, it is impossible to apply this method directly to a commercial CAD/CAM system. In this paper an algorithm is developed to approximate a ball rolling blend surface into Bezier surface patches. Least square method is applied to obtain proper Bezier surface patches under a given tolerance. The Bezier surface patches have degree three or more and guarantee VC1-continuity.

• Journal of the Korea Institute of Building Construction
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• v.12 no.6
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• pp.607-614
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• 2012

In this study, the evolution of the electro-mechanical impedance (EMI) of a piezoelectric (PZT) patch embedded in fresh cement paste was investigated to discuss the possibility of monitoring the setting process of cement-based materials using an EMI sensing technique. A tailored thin square PZT patch was embedded in cement paste before casting, and EMI signatures of the embedded patch were continuously measured from casting up to 12 hours. A standard penetration resistance test was performed to compare and correlate the evolution of EMI during the setting process. The results showed that EMI responses differ according to the age of the cement paste, and that the behavior of the EMI resonance peak has a clear correlation with the penetration resistance of the cement paste. Based on the results, it is concluded that an EMI sensing technique using embedded PZT patch can be effectively applied to monitor the setting process of cement-based materials.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.339-342
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• 2003

This paper newly proposes a mesh regularization method for the enhancement of the efficiency in sheet metal forming analysis. The regularization method searches for distorted elements with appropriate searching criteria and constructs patches including the elements to be modified. Each patch is then extended to a three-dimensional surface in order to obtain the information of the continuous coordinates. In constructing the surface enclosing each patch, NURBS(Non-Uniform Rational B-Spline) surface is employed to describe a three-dimensional free surface. On the basis of the constructed surface, each node is properly arranged to form unit elements as close as to a square. The analysis results with the proposed method are compared to the results from the direct forming analysis without mesh regularization in order to confirm the validity of the method.