• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.5
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• pp.355-365
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• 2017

In this paper, we propose the design of a dual-band GPS antenna using in-direct feeding pads. The antenna consists of an upper patch for the GPS L1 band, a lower patch for the GPS L2 band, and two pads on the middle layer for feeding the two radiating patches. A hybrid chip coupler with a phase difference of $90^{\circ}$ is employed at the two feeding ports for achieving a broad circular polarization (CP) bandwidth. The proposed antenna shows bore-sight gains of 3.0 dBic(L1) and 5.1 dBic(L2), and axial ratios of 3.3 dB(L1) and 0.3 dB(L2) by measurement. The active element patterns of the fabricated array with 7 elements show bore-sight gains of -0.4 dBic (L1) and -2.4 dBic(L2), respectively. It proves that the proposed antenna structure is suitable for use in GPS array applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.868-875
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• 2000

GPS(Global Positioning System) is widely used in the navigation system, ITS(Intelligence Transportation System), and mobile communications. Recently, it is considered to combine the GPS receiver with the CLONASS for the improvement of performance and accuracy. In this paper, a wideband aperture-coupled patch antenna with circular polarization is designed and implemented for the use of CPS/GLONASS combined receiver. The measured characteristics of the manufactured antenna shows the - l5 dB bandwidth of 220 MHz and the axial ratio less than 2.1 dB, and it satisfies the requirements of the GPS/GLONASS antenna.

• Journal of Positioning, Navigation, and Timing
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• v.7 no.2
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• pp.105-112
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• 2018

This paper manufactured an active GPS antenna for ground vehicles and presented a method to verify the performances of the antenna and component technology of the low noise amplifier (LNA) board manufacturing. The manufactured GPS antenna is an active antenna where microstrip patch and LNA board were combined. The main performances were standing wave ratio, antenna gain, and axial ratio, and all satisfied the target specifications. The proposed component technology can be utilized as a basis data in which the performance of LNA board can be compensated in the mass production process inspection, and employed as a method to verify whether antennas are properly working in environmental tests.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.145-148
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• 1998

In this paper, a microstrip antenna is designed using a rectangular patch. To find characteristics of the antenna, computer simulations of the rectangular single microstrip patch antenna are performed with changing width. And we compared the result of computer simulation with the experimental value. Through the results, we found that the 3-D FDTD method is an effective method for designing microstrip patch antenna. According to simulation the resonant point has been found it in the frequency received from GPS satellite. It is thought that make it match by adjusting the feedpoint.

• 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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.4
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• pp.88-94
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• 2007

This paper deals with the performance analysis of 3-dimensional array antenna by DOA estimation and beamforming in GPS receiver for performance improvement by interference elimination. The array antenna in GPS receiver can improve the system performance by estimating DOA of arriving signal direction, making the main beam for desired direction and elimate the jammer signal by nulling while keeping the GPS signal direction by spatial filtering. In this paper, we propose five types of 3-dimensional array antenna and analyze the estimation error via MUSIC algorithm which is used for the estimation of DOA of arrived signal and beamforming performance. In analyzing DOA performance, we measure DOA estimation error, while in analyzing beamformig performance, we measure BER. In beamforming performance analyzing, we use various jammer power and the existence of GPS signal and angle spread. By performing through the computer simulation, Curved (B) 7-element antenna in proposed 3-dimensional array antenna exhibits the superior performance in the DOA estimation, estimation error, BER characteristic and angle spread compared to the rest four array antenna types.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.138-144
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• 2008

In this paper, we propose a novel single-feed dual-band circular polarization square patch antenna for GPS(global positioning system)/DMB(digital multimedia broadcasting) receiver. The proposed antenna has folded slots at the 4 corners and a diagonal slot at the center of the square patch. The measured -10 dB impedance bandwidths of the proposed antenna were 84 MHz ranging from 1.516 GHz to 1.600 GHz for the low frequency band(GPS) and 109 MHz ranging from 2.596 GHz to 2.705 GHz for the high frequency band(DMB). The measured peak linear antenna gains of the proposed antenna were 6.23 dBi at 1.575 GHz for GPS and 6.97 dBi at 2.642 GHz for DMB band.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.4
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• pp.198-205
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• 2005

In this paper, the miniaturization of aperture-coupled RHCP patch antenna for the GPS system is treated. Circularly polarization characteristics is implemented by truncating diagonal corners of the square patch. Antenna size is reduced by inserting four uniform slits at the patch edges, which was equivalently lengthened the surface current by meandering it, This antenna uses aperture-coupled feeding structure with crossed-slot shape in order to give easy miniaturization of RHCP patch antenna. Simulated and measured results show that $42.7\%$ lower antenna size is obtained, and also $56\%$ lower -10dB bandwidth and $38.5\%$ lower 3dB AR bandwidth are obtained. when the proposed design scheme is applied to a commercial GPS antenna structure, $42.9\%$ lower patch size and $56\%$ lower 3dB AR bandwidth compared to commercial antenna at the same frequency are obtained.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.3
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• pp.382-389
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• 2013

In anti-jamming GPS receiver, adaptive signal processing techniques in which the radiation pattern of adaptive array antenna of elements may be adaptively changed used to reject interference, clutter, and jamming signals. In this paper, I describes adaptive signal processing technique using the sample matrix inversion(SMI) algorithm. This adaptive signal processing technique can be applied effectively to wideband/narrowband anti-jamming GPS receiver because it does not consider the satellite signal directions and GPS signal power level exists below the thermal noise. I also analyzed the effects of covariance matrix sample size and diagonal loading technique on the system performance of five-element circular array antenna. To attain near optimum performance, more samples required for calculation covariance matrix. Diagonal loading technique reduces the system nulling capability against low-power jamming signals, but this technique improves robustness of adaptive array antenna.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.3
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• pp.48-55
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• 2006

This paper describes the antenna based GPS anti-jamming technology called CRPA(Controlled Reception Pattern Antenna), which used $2{\times}2$ array elements. In this system, the main functions are the antenna complex weight control and the GPS digital I/Q VM(Vector Modulator). To update the VM's I/Q complex weights, the PC based DAC(Digital to Analog Converter) module was also used and the two analog output voltages were applied to the $2{\times}2$ array elements to synthesize the null pattern. In the study, we also simulated the $2{\times}2$ GPS array null patterns to compare the null depth with experimental results. The VM was also modified at the frequency of 1.575GHz for the GPS L1 and controlled by the PC based VM software.