• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11B
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• pp.1600-1606
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• 2001

Resonant frequency in rectangular microstrip patch antenna on anisotropic substrates with airgap and superstrate are analyzed. Dyadic Green function is derived for selected anisotropic material by constitutive relation. From these results, integral equations of electric fields are formulated using Fourier transform in space region. The electric field integral equations are discretized into the matrix form by applying Galerkin\`s moment method. Sinusoidal functions are selected as basis functions because they resemble in the actual standing wave on the patch. To verify the validity of numerical result, we compare our result with existing one and get a good agreement between them. From the numerical results, the resonant frequency in the variation of air gap, patch length and anisotropy ratio are presented and analysed.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.433-434
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• 1988

Rectangular microstrip antenna with parasitic element is analyzed. Radiation admittance and equivalent circuit parameters between rectangular microstrip antenna and parasitic element are obtained by using equivalent ${\pi}$-network parameters of the slit in the wall of the parallel plate waveguide filled with homogeneous dielectric. The return loss is calculated and measured as a function of frequency with gap width 0.5mm between the patch and parasitic element. The experimental results are in fairly agreement with calculated values.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.101-107
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• 2018

The impedance bandwidth and radiation characteristics of an aperture-coupled microstrip line-fed patch antenna (ACMPA) with a high permittivity (${\varepsilon}_r=10$) feed substrate suitable for integration with a monolithic microwave integrated circuit (MMIC) are investigated for various feed substrate thicknesses through an experiment and computer simulation. The impedance bandwidth of an ACMPA with a high permittivity feed substrate increases as the feed substrate thickness decreases. Furthermore, the front-to-back ratio of an ACMPA with a high permittivity feed substrate increases and the cross-polarization level decreases as the feed substrate thickness decreases. As the impedance bandwidth of an ACMPA with a high permittivity feed substrate increases and its radiation characteristics improve as the feed substrate thickness decreases, the ACMPA configuration becomes suitable for integration with an MMIC.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.3
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• pp.62-72
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• 2022

In this study, a miniaturized GPS band(L₁ : 1.575 GHz) antenna that can be mounted on a small drone is proposed. The miniaturization was designed by applying the perturbation method based on the λ/4 microstrip antenna and lengthening the current path at the edge of the patch. The miniaturized antenna was fabricatred such that it could be attached to the surface of styrofoam(ε_r=1.06, t=10 mm) having a size of 10 mm × 9 mm × 10 mm (0.05 λ × 0.05 λ × 0.05 λ). The thickness and length of the feeding line and the spacing between short stubs were adjusted for impedance matching. S₁₁ was found to be -18.8 dB at the center frequency of the fabricated antenna, 1.575 GHz. The radiation pattern measurement results show that the maximum gain of E_θ is 1.87 dBi in 0 directions in the xz-plane, and that E_θ is an omnidirectional characteristic with an average gain of -1.7 dBi in the yz-plane. It was found that the antenna can be used as an ultra-small microstrip antenna, which can be mounted on a small dron for GPS, and is capable of preserving a reduction ratio of 98.8% as compared to a λ/2 microstrip patch antenna.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.10
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• pp.80-89
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• 2008

Patch antennas with an array of pins interconnecting the patch and the ground (Pin array patch antennas) are fabricated and their characteristics are measured. The radiation characteristics of pin array patch antennas are compared to those of conventional patch antennas. The suppressions of the radiation in horizontal directions in E-plane and H-plane are more than 10 dB and 4 dB, respectively. The forward radiation is increased, while the backward radiation is decreased. The directivity is improved because the half-power beamwidth of radiation patterns in both E-plane and H-plane is reduced. The resonance frequency of a pin array patch antenna increases as the pin radius of a pin amy patch antenna increases. An optimum pin radius of a pin array patch antenna exists for the maximum suppression of the radiation in horizontal directions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3205-3214
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• 1996

In this paper, the microstrip phased array antennas with coupling-slots for the base station of mobile communication is proposed and anlyzed with accurate analysis method which is based on both reciprocity principle and full-wave analysis. The basis functions used for the numerical analysis are determined depending upon the accuracy, convergence properties of the solution, and the computation time. The patch uses 3 EB mode and the slot uses IPWS mode. The designed phased array antenna has 8 slot-coupled microstrip patch array elements and the beam scanning capability is obtained by using the 4-bit PIN-diode phase shifters as switching devices which are consisted of the loaded line phase shifters for 30.deg. and 60.deg. and the reflection type phase shifters for 90.deg. and 180.deg. repectively. The 4-bits phase shifters which aremade by connecting each phase shifter have about 2.deg.-3.deg. phase errors and their insertion loss are about 3dB for each phase state. The fabricated 8-element phased array antenna with 4-bits phase shifters provides 12.deg.-14.deg. beamwidths depending on the scanning angle and is capable of scanning its beam to .+-.45.deg. with 9.deg. intervals, and the gain 12dBi. The overall results show that the slot-coupled phased array antenna has great advantages of wideband, high gain and reduced spurious radiation. Also, the antenna can be made small and thin. Furthermore, the scanning property of this antenna allows for its application in several areas, such as mobile communication system and PCS.

• Journal of IKEEE
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• v.13 no.3
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• pp.72-79
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• 2009

This paper describes a compact microstrip active antenna with dual polarization. The antenna, receiving both a left-hand circularly polarized wave and a right-hand circularly polarized wave, has a function of polarization diversity. A square-shaped empty room is located on the inside of the microstrip radiator so that the size has been reduced. And slots are added around feeding point to improve input matching. Also, amplifier and switching circuitry are placed at the empty room to increase antenna gain and to select one of the circular polarizations, respectively. The proposed antenna has been applied to GPS(global positioning system). The measurement results show that it has 10dB-impedance bandwidth, 3dB axial bandwidth of about 50MHz, 3dB beamwidth of 90degree, and gain of 13dBi, respectively, for RHCP. Also, it has 3dB axial bandwidth of about 50MHz, 3dB beamwidth of 84 degree, and gain of 12dBi, respectively, for LHCP.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.35-40
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• 1989

In this paper, a new method which simultaneously gives the radiation conductance and susceptance of the rectangular microstrip patch antenna. This solution is derived from the load admittance of the equivalent ${\pi}-$network circuit of the slitted parallel-plate waveguide filled with homogeneous dielectric. Our theoretical results for the radiation admittance are compared with other theoretical results. Also, our theoretical return loss and resonant frequency which are calculated by use of the equivalent transmission line model are in fairly good agreement with the experimental results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.1
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• pp.91-97
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• 2005

In the mobile antenna systems for satellite multimedia communications, the active way antenna having a low sidelobe antenna pattern is described in this paper. This designed and fabricated array antenna is satisfied with international beam pattern regulation on moving states. The subarray of the proposed mobile antenna system is arranged with a stair-planar structure and non-periodic array spacing. This subarray is designed with three-layered microstrip patch as both receiving and transmitting radiator of which are improved with antenna gain and bandwidth. Also, the optimum subarray spacing is designed to make the lowest sidelobe pattern by genetic algorithm. In addition, the characteristics of a GA-perturbed array are investigated from simulated and measured beam pattern results.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.183-185
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• 2010

A 2.4 GHz dual-polarized antenna for a Doppler radar is studied. The proposed dual-polarized antenna using a stacked annular ring patch with two co-centric gap-coupled feed lines and a $90^{\circ}$ hybrid exhibits fairly good performance of 22 dB isolation at a center frequency of 2.4 GHz. Using a $90^{\circ}$ hybrid, a right-handed circular polarization for the transmitter and a left-handed circular polarization for the receiver are implemented. The gain of the designed antenna is about 0 dBi over operating frequencies. The antenna size including a ground plane is only $40{\times}40\;mm^2$.