• ETRI Journal
• /
• v.33 no.2
• /
• pp.163-168
• /
• 2011

A Fabry-Perot cavity (FPC) antenna producing both high-gain and circularly-polarized (CP) behavior is proposed. To increase antenna gain and obtain CP characteristics, a superstrate composed of square patches with a pair of truncated corners is placed above the linearly polarized patch antenna with an approximately half-wavelength distance from the ground plane at the operating frequency. The proposed antenna has the advantages of high gain, a simple design, and an excellent boresight axial ratio over the operating frequency bandwidth. Moreover, used in an FPC antenna, the proposed superstrate converts a linear polarization produced by a patch antenna into a circular polarization. In addition, the cavity antenna produces left-hand circular-polarization and right-hand circular-polarization when a patch antenna inside the cavity generates x-direction and y-direction polarization, respectively. The measured and simulated results verify the performance of the antenna.

• Journal of Satellite, Information and Communications
• /
• v.11 no.1
• /
• pp.37-40
• /
• 2016

We designed an antenna structure with the circular polarization metamaterial superstrate which increases the directivity of the primary antenna as a lens. The metamaterial superstrate removes the necessity of the array antenna and complicated feed. Plus, it provides the Fabry-perot cavity with the circular polarization. With regard to the primary antenna, a CRLH antenna is adopted to have the size-reduction from the conventional half-wavelength patch antenna.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.4
• /
• pp.1780-1785
• /
• 2015

In this paper, the adaptive particle swarm optimization (APSO) algorithm is employed to design a gain-enhanced antenna with a reflector for energy harvesting. We placed the reflector below the main radiating element. Its back-radiated field is reflected and added to the forward radiated field, which could increase the antenna gain. We adopt the adaptive particle swarm optimization (APSO) algorithm, which improves the speed of convergence with a high frequency solver. The result shows that performance of the optimized design successfully satisfied the design goal of the frequency band, gain and axial ratio.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2005.11a
• /
• pp.231-234
• /
• 2005

In this paper, Dual-polarized Tx/Rx antenna for RFID reader is designed and fabricated to apply to RFID reader. Each feeding network of Tx/Rx is designed to improve the port-isolation and cross-polarization, and sequential rotation feeding scheme has been applied to increase of axial ratio bandwidth. Measured results show that 2.35dBi of antenna gain in 900MHz$\sim$928MHz, 150MHz of 3dB axial ratio bandwidth, -38dB$\sim$-40dB of port-isolation, and -30dB$\sim$-40dB of cross-polarization.

• Journal of IKEEE
• /
• v.13 no.3
• /
• pp.72-79
• /
• 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 Institute of Electronics and Information Engineers
• /
• v.51 no.3
• /
• pp.202-209
• /
• 2014

In this paper, we analyzed the effects by multi-stacking superstrates over the circular-polarized patch antenna. The previous works considered a single-layered superstrate or a superstrate with multiple layers, and did not almost consider the axial ratio at the performance analysis. First, the effect of center frequency shift is analyzed by the variation of air-gap height between patch antenna and superstrate. The center frequency is down-shifted at the smaller air-gap height and has almost the same frequency as patch antenna at the air-gap height of $005{\lambda}_0$. Second, the antenna performance is analyzed by multi-stacking superstrates with the air-gap height of $005{\lambda}_0$. As the number of multi-stacked superstrates increase, antenna gain has a linear increase and axial ratio is exponentially deteriorated. In addition, it has also been observed that the antenna performance has the same trend with the number of multi-stacked superstrates as the thickness of superstrate increases. Finally, we confirmed that it is possible to design the CP patch antenna with the scalable gain and less than 3dB axial ratio by stacking the superstrate.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.12
• /
• pp.1427-1434
• /
• 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 Advanced Navigation Technology
• /
• v.6 no.2
• /
• pp.113-118
• /
• 2002

In this paper, an internal GPS antenna for mobile phones is designed and fabricated. For the miniaturization of the antenna, high permittivity dielectric substrate((${\varepsilon}_r$=90) and small ground plane ($13mm{\times}13mm$) are used. To increase the receive gain, the antenna is composed with LNA(Low Noise Amplifier). Results of the manufactured antenna($13mm{\times}13mm{\times}8mm$) show that the maximum antenna gain is about 12 dBi, the axial ratio is less than 3 dB, and the current consumption of LNA is less than 4 mA.

• ETRI Journal
• /
• v.34 no.5
• /
• pp.767-770
• /
• 2012

This letter presents a novel compact circularly polarized patch antenna for Global Positioning System/Global Navigation Satellite System (GPS/GLONASS) applications. The proposed antenna is composed of a simple square radiating patch fed by a capacitive dual-feeder to increase the impedance bandwidth and a lumped element hybrid coupler to achieve the broadband characteristic of the axial ratio (AR). The realized antenna dimensions are $28mm{\times}28mm{\times}4mm$, which is the most compact size among the dual-band GPS/GLONASS antennas reported to date. The measured results demonstrate that the proposed antenna has a gain of 2.5 dBi to 4.2 dBi and an AR of 0.41 dB to 1.51 dB over the GPS/GLONASS L1 band (1.575 GHz to 1.61 GHz).