• Journal of IKEEE
• /
• v.24 no.1
• /
• pp.368-371
• /
• 2020

In this paper, we propose a linear tapered slot rectifying antenna for a portable UHF-band RFID system. Since the proposed rectifying antenna does not use a dielectric substrate, the planar antenna is implemented with a thin metal thickness. The rectifier circuit converts input RF power into output DC voltage using a voltage doubler circuit based on two anti-parallel schottky diodes. The rectifying antenna is integrated by the voltage doubler circuit into a linear tapered slot antenna. For conjugate impedance matching of the rectifying circuit and the linear tapered slot antenna, the source-pull method was utilized by adjusting the angle of the tapered slot and the length of the antenna feed line. The proposed antenna prototype has been verified with the electrical and radiation characteristics through RF-DC conversion and far-field radiation test in open space measurement environment. Finally, the proposed antenna is realized to 0.23-wavelength (75 mm) and 0.18-wavelength (60 mm) at 915 MHz center frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.1
• /
• pp.16-23
• /
• 2015

In this paper, a bent microstrip patch antenna, which is suitable for band-type wearable devices and RF configuration, to be used in the WCDMA2100 mobile network is proposed. The proposed antenna using RF configuration which is consisted of separated Tx and Rx frequency band is designed to operate or function in WCDMA2100 Tx frequency band only and it is not strongly affected by the human body because of the conductor at the bottom side. At both flat case and bent case, the proposed antenna's maximum gain satisfies at least 5.3 dBi, and its -6 dB return loss bandwidth is wider than 20 MHz. The simulated surface absorption rate($SAR_{1g}$) result is under 0.7 [W/kg]. The proposed antenna suits in band-type wearable devices which is worn on wrists or arms.

• Journal of information and communication convergence engineering
• /
• v.6 no.2
• /
• pp.169-171
• /
• 2008

An internal antenna for small mobile systems is proposed to support the DVB-H system. It consists of two antenna elements, which are a folded planar monopole for DVB-H and PIFA for GSM/DCS/PCS, and a meander line and RF cable are used to increase the ground plane. Experimental results of the antenna are presented.

• Aerospace Engineering and Technology
• /
• v.4 no.1
• /
• pp.103-107
• /
• 2005

There is an X-band transmission system in KOMPSAT-2 in order to downlink the acquired image data in high speed. KOMPSAT-2 employs a steerable high gain X-band antenna for that purpose. During the ground test, the X-band RF radiation is so strong that it has to be controlled for safety, while spacecraft needs to keep flight configuration. Also in a launch site of which all test facilities are the subjects of strict radiation control, the antenna system should be tested again without any change in the configuration. To limit the actual radiation of RF power, an antenna hat was manufactured and thoroughly tested to demonstrate the spacecraft safety when using it.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.4
• /
• pp.49-53
• /
• 2018

Parabolic offset antenna is widely used for wireless communication system. The general structure of parabolic offset antenna system is composed of supporting stand and RF devices under parabolic reflector. However sidelobe distortion in gain pattern is occurred by supporting stand and RF devices. Depending on position of subsidiary devices, angle of sidelobe distortion can be changed. In this paper we describe method for sidelobe distortion suppression using raytracing. We calculate 3D vector for sidelobe distortion suppression zone by raytracing method and compare when subsidiary device is in sidelobe distortion suppression zone or not. By comparison, we show method for parabolic antenna sidelobe distortion suppression.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.11
• /
• pp.55-60
• /
• 2008

This paper proposed a dual-band RF switch using a Composite Right/Left Handed transmission line(CRLH TL) and PIN diode. RF switch is usually consist of $\lambda/4$ Right Handed transmission line(RH TL) and PIN diode. The dual band characteristics of RF switch was achieved by using CRLH transmission line instead of RH transmission line. CRLH Open-Stub was designed for resolve to reduction of isolation due to Package Inductance of PIN diode. The proposed RF switch was designed at GSM and DCS frequency-band. The measurement results showed a good agreement with theoretical result.

• 한국ITS학회:학술대회논문집
• /
• 2003.11a
• /
• pp.316-319
• /
• 2003

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.6
• /
• pp.689-697
• /
• 2016

In this paper, we design and implement SPA (Switched Parasitic Antenna) antenna which can control its beampattern using multiple parasitic elements. By applying SPA antenna to wireless communication system and implementing beamforming scheme, we show that SPA antenna can be used to improve the performance of wireless communication systems. SPA antenna consists of a single active antenna and multiple parasitic elements around the active one, and can control its beampattern by switching the parasitic elements. Using this characteristic of the SPA antenna, it is possible to impelemtent beamforming technique with single RF chain, which enables to design low cost, low complexity and low power wireless communication systems. In order to verify the beamforming gain, we measure and analyze the system level performance, such as SNR, PER, and throughput.

• Journal of Advanced Navigation Technology
• /
• v.22 no.4
• /
• pp.311-318
• /
• 2018

In this paper, test-bed for the evaluation of wireless communication system on a small launch vehicle is proposed. The proposed test-bed consists of antenna test-coupler, RF attenuators, and RF switch modules. The antenna test-coupler isolates antennas for each band and transmits / receives wireless signals. The RF attenuator and switch are used for path selection of testing signal path. In design and measurement result of the antenna test-coupler, the antenna test-coupler has shielding effect higher than 39.3, 47.1, 56.1 dB at UHF-, S-, X-band. Through testing on small launch vehicle wireless communication system, we were able to successfully transmit and receive data between each test system and launch vehicle with antenna path switching.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.8
• /
• pp.710-717
• /
• 2015

In this paper, we design an array antenna structure based on a patch ESPAR(Electronically Steerable Parasitic Array Radiator) antenna with three elements for reliable communication in high-speed railway wireless communication. The ESPAR antenna consists of the active element with a single RF-chain and the parasitic elements surrounding an active element. The ESPAR antenna is capable of beamforming by adjusting the reactance of the parasitic element. We propose a vertical array antenna structure based on the patch ESPAR antenna and simulate it according to the change of the number of antennas and the distance between antenna rows. The simulation results show that we can get the maximum beam gain and highest directivity when the distance between antenna rows is ${\lambda}$.