• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1427-1434
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• 2008

Compact quadruple inverted-f antenna(QIFA) with circular polarization for GPS receiver is proposed. Radiation efficiency is decreased when 4-port antenna is smaller. A new matching method is proposed by considering both a return loss at one port and mutual coupling between ports to increase radiation efficiency. Experimental results show that the proposed QIFA has a 3-dB beamwidth of more than 120 degrees and a front-to-back ratio of more than 15 dB. Also, the QIFA has the peak gain of -2.5 dBic and the axial ratio under 0.5 dB.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.3
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• pp.25-32
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• 2021

In this paper, the Magneto-Electric(ME) dipole array antenna with dual-polarization in the X-Band is proposed and it is implemented and measured. The proposed array antenna is composed of 32 single ME dipole antenna and a Teflon PCB. 1 × 1 ME dipole antenna is implemented dual-polarization by radiating vertical polarization and horizontal polarization from two pairs of radiators. 2-port feeding structures are realized by lamination process using LTCC. And, each port independently feeds the radiator through a Γ-shaped feeding strip with isolation between ports. The Teflon PCB used in the antenna array has a 4-layer structure, and 2-port is fed through the top and bottom layers. The λ_g/4 transformer is applied to the transmission line of the Teflon PCB for impedance matching of the arrayed antenna and the Teflon PCB, and the optimal parameters are obtained through simulation. The measured maximum antenna gains of port 1 was 18.2 dBi, Cross-pol was 1.0 dBi. And the measured maximum antenna gains of port 1 was 18.1 dBi, Cross-pol was 3.2 dBi.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.2
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• pp.50-56
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• 2014

This paper describes the design, fabrication, and measurement of a 4-port femtocell MIMO antenna for LTE 700MHz(Band12, 13, 14, 17, 28, 44) applications. Based on microstrip patch antenna, an impedance matching is achieved by short pin. In order to obtain sufficient bandwidth and isolation between antenna elements in a limited dimension, a cross decoupler is used. With a Voltage Standing Wave Ratio (VSWR)${\leq}2$, the measured result of the fabricated antenna provides 105MHz(0.698~0.803MHZ) bandwidth and shows the gain with 1.97dBi and isolation above 13dB. As one of the key parameters for MIMO performance evaluation, correlation coefficient of MIMO is achieved within 0.2.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1037-1044
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• 2021

In this paper, we propose DLP(Dual Linear Polarization) array antenna for 3.5 GHz band. The proposed antenna has 1×4 array antenna and design two port network. A cross shape is inserted at the bottom of the patch for impedance matching. The size of each patch antenna is 18.85 mm(W1)×18.85 mm(L1), array antenna is designed on the FR-4 substrate, which is 236.0 mm(W)×60.2 mm(L), thickness (h) 1.6 mm, and the dielectric constant is 4.3. From the fabrication and measurement results, bandwidths of 70 MHz (3.54 to 3.61 GHz) for input port 1, 75 MHz (3.55 to 3.625 GHz) for input port 2 are obtained on the basis of -10 dB return loss and transmission coefficient S21 is under the -20 dB. Also, cross polarization between two port obtained.

• Journal of Navigation and Port Research
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• v.31 no.6
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• pp.503-507
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• 2007

In this paper, the ultra-widebend, microstrip patch antenna with the bandwidth of 3 GHz was implemented for ultra-wideband(UWB) wireless communication applications. In order to cover the very wide bandwidth of 3 GHz, a multi-resonance antenna was designed, each resonance frequency was separated into five frequency bend, 7.5, 8.1, 8.7, 9.3, and 9.9GHz with the interval of 600MHz BW. And for wideband characteristics of each antenna, U-slot antennas were designed at each center frequency. Designed five U-slot antennas were connected in series for multi-resonance of 3GHz BW and wideband matching was also designed for impedance matching transmission line calculated. The relative dielectric constant, the height, the loss tangent of the PCB substrate were ${\epsilon}_r=4.8,\;h=0.6$ and loss tangent=0.0009 respectively. The implemented antenna's radiation patterns and gain were directivity characteristics and $1.46{\sim}4.08dBi$ at the five separated center frequency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.55-56
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• 2017

In this paper, a wideband loop antenna is designed using a CPW feeding method for indoor digital TV applications. The proposed loop antenna consists of a square loop and two circular sectors which connect the loop with central feed points, and the CPW feed line is inserted in the lower circular sector. The CPW feed line is designed to match with the 75 ohm port impedance for DTV applications, and the ground slots are etched in order to improve the impedance matching in the middle frequency region. The optimized antenna is fabricated on FR4 substrate, and the experiment results show that it operates in the frequency band of 463-1,280 MHz for a VSWR < 2, which assures the operation in the DTV band.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.581-586
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• 2020

In this paper, the design process and method for a compact wideband loop antenna for terrestrial digital TV (DTV) and ultra high definition (UHD) TV applications was proposed. Horizontal slits were added on the two circular sectors of the proposed loop antenna in order to miniaturize the existing wideband loop antenna consisting of a square loop and two circular sectors. A CPW transmission line was inserted in the center of the lower circular sector as a feed line. The CPW feed line was designed using the 75 ohm port impedance for DTV and UHD TV applications, and a tapered center-signal line was designed to improve the impedance matching. The final designed antenna was fabricated on an FR4 substrate with a thickness of 0.8 mm. The experiment results show that the proposed compact loop antenna operates in the frequency band of 444.3-820.1 MHz for a VSWR < 2, which fully covers the DTV and UHD TV bands.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.8
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• pp.42-50
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• 2007

This paper presents design methods for dual-frequency(2.4/5.8GHz) active receiving antennas. The proposed active receiving antennas are designed to interconnect the output port of a wideband antenna to the input port of an active device of High Electron Mobility Transistor directly and to receive RF signals of 2.4GHz and 5.2GHz simultaneously where the impedance matching conditions are optimized by adjusting the length of $1/20{\lambda}_0$(@5.8GHz) CPW transmission line in the planar antenna The bandwidth of implemented dual-frequency active receiving antennas is measured in the range of 2.0GHz to 3.1GHz and 5.25GHz to 5.9GHz. Gains are measured of 17.0dB at 2.4GHz and 15.0dB at 5.2GHz. The measured noise figure is 1.5dB at operating frequencies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1492-1497
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• 2017

In this paper, a design method for a CPW-fed wideband loop antenna for indoor digital TV applications is studied. The proposed loop antenna consists of a square loop and two circular sectors which connect the loop with central feed points, and the CPW feed line is inserted in the lower circular sector. The CPW feed line is designed to match with the 75 ohm port impedance for DTV applications, and the ground slots are etched in order to improve the impedance matching in the middle frequency region. The effects of the gap between the circular sectors and the location and dimension of the ground slots on the input reflection coefficient and gain characteristics are examined to obtain the optimal design parameters. The optimized antenna is fabricated on FR4 substrate, and the experiment results show that it operates in the frequency band of 463-1,280 MHz for a VSWR < 2, which assures the operation in the DTV band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1098-1106
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• 2007

This paper presents active antenna diplexers implemented into an ultra-wideband CPW(Coplanar Waveguide) fed monopole antennas. The proposed active antenna diplexer is designed to direct interconnect the output port of a wideband antenna to the input port of two active(HEMT) devices, where the impedance matching conditions of the proposed active integrated antenna are optimized by adjusting CPW(Coplanar Waveguide) feed line to be the length of 1/20 $\lambda_0$(@5.8 GHz) in planar type wideband antenna. The measured bandwidth of the active integrated antenna shows the range from 2.0 GHz to 3.1 GHz and from 5.25 GHz to 5.9 GHz. The measured peak gains are 17.0 dB at 2.4 GHz and 15.0 dB at 5.5 GHz.