• Journal of electromagnetic engineering and science
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• v.2 no.1
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• pp.50-55
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• 2002

In this paper, Ive propose a bow-tie-shaped meander slot antenna find by a microstrip line to achieve compact size as well as wideband characteristic. While conventional bow-tie slot antennas exhibit wide band characteristic, they have relatively large size. On the other hand, the meander slot antennas are very small, but they reveal quite narrow bandwidth (typically less than 1 %). To realize miniaturized antennas balling large bandwidth, combination of the bow-tie slot and the meander slot geometries is proposed in this paper. Theoretical results show that the proposed antenna with uniform slot width is 65.5 % smaller than that of the conventional bow-tie antenna in size, while the bandwidth is 3 times larger than that of the meander slot antenna. Moreover, the non-uniform slot width antenna shows 60 % smaller in size and about 3.5 times wider in bandwidth than the previous antennas. Measured antenna performance reveals excellent agreement with the predicted values.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.535-540
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• 2004

In this paper, We proposed a rectangular slot antenna with CPW feeder. Slot antennas fed by CPW are attractive due to the simple fabrication simplicity and ease of integration with active devices. This antenna consists of two parts, inner patch and outer patch to realize wide-band antenna by multi-frequency. Also, We fabricated a proposed rectangular slot antenna, confirm characteristics of multi-frequency by tuning antenna parameters, inner antenna's location and size. The experimental results show that each resonant frequency of a fabricated antenna is measured at almost 1, 9GHz, 2.8GHz, 3, 5GHz, 4, 9GHz. In radiation patterns each resonant frequency, radiation pattern 4-th resonant frequency is the same ad that of TM11 in patch antenna. Therefore, the experimental and theoretical results shows that a proposal rectangular slot antenna have triple resonant frequencies.

• Journal of Advanced Navigation Technology
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• v.27 no.3
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• pp.281-286
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• 2023

This paper proposes a design of a wideband array antenna involving the downlink bands of fixed satellite service (FSS) and broadcasting satellite service (BSS) by applying two mixed patch sets. The proposed antenna is implemented on FR4 substrate by arranging rectangular patches in 6 by 2. To design a wideband antenna (10.7~12.75 GHz) covering both FSS downlink bands (10.7~10.95 GHz, 11.2~11.45 GHz) and BSS downlink bands (11.7~12.5 GHz, 12.2~12.75 GHz, 11.7~12.2 GHz), rectangular patches working at 11.5 GHz and 12.5 GHz are arranged alternately, and thus the proposed antenna can obtain a wide bandwidth equivalent to 30.8% of the center frequency. The proposed antenna was fabricated and measured, and the results are well matched with the simulated ones. From the performances, the proposed antenna can be applied to the receiving antenna for FSS and BSS downlinks.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.748-754
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• 2000

A novel single feed wide band CP stacked microstrip antenna using crossed slots has been designed, fabricated and measured. For the single rediating element the designed 10dB return loss bandwidth is 34.5%99.45~13.54 GHz), 3dB axial ratio bandwidth is 18.7%(11.17~13.39GHz), and 6 dB gain bandwidth is 29%(10.21~13.64GHz). For the 2$\times$2 array designed using a sequential rotation method, the 10dB return loss bandwidth is 35.9%(9.69~13.94GHz), 3dB axial ratio bandwidth is 34.6GHz (9.93~14.03GHz), and 6dB gain bandwidth is 27.4%(10.35~13.6GHz). For the fabricated 8$\times$8 array antenna, the 10dB return loss bandwidth is 27.3%(10.17~13.41GHz), 3dB axial ratio bandwidth is 27.9GHz(10.1~13.4GHz), and the radiation pattern is good agreement with theory. This antenna can be used for broadband applications for communications or broadcasting in Ku band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.6 s.109
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• pp.511-518
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• 2006

In this paper, a small RFID tag antenna in UHF band which has bandwidth-enhanced characteristic is proposed. The shape of the proposed antenna is a meander antenna to have size-reduced characteristic, and it consists of two radiators which make dual resonance in adjacent frequency to enhance bandwidth. By adjusting length and location of each radiator, the proposed antenna can make dual resonance at arbitrary location on the Smith chart, which is able to make impedance matching with RFID tag chip in wide frequency range. And it is apparent that the proposed antenna can have bandwidth-enhanced characteristic according to the simulated and measured results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.3
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• pp.159-166
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• 2018

Herein, a non-Foster matching circuit is designed to improve the impedance matching characteristics of small antennas in the VHF and UHF bands. The proposed non-Foster circuit is designed to operate with negative capacitance in a wide frequency band from 50 MHz to 1,000 MHz for use in various communication bands. To ensure the stability of the non-Foster circuit with conditional stability, the open-circuit stability condition of Linvill was satisfied, and the circuit was fabricated using the FR-4 substrate. The fabricated non-Foster circuit was combined with a small antenna to verify its performance by measuring the return loss and received power in the FM, DMB, and GSM bands. The measured return loss was improved from -6 dB to -30 dB, and the measured received power was improved from 0.5 dBm to 5.2 dBm.

• Journal of the Korea Society of Computer and Information
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• v.18 no.3
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• pp.27-34
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• 2013

A wideband patch antenna fed by an L-strip feeder is studied. The objective of this paper is to design small wideband antenna for 3G and 4G wireless mobile communication service. The enhanced features were confirmed and proved by comparing the proposed antenna with the antennae that have been reported in the relevant literatures. Measurement results confirm that an impedance bandwidth($VSWR{\leq}2$) of 636MHz(32.5%, fo=1,960MHz) is achieved at 3G and 4G frequency band for L-strip-fed triangular patch antenna. In general, probe feed has only the parasitic reactance caused by the probe, which reduces the bandwidth performance of the antenna. The experimental results proved that the effects of improvement could be achieved because the proposed antenna is capable of compensating the parasitic reactance from the feeding mechanism. The studied antenna can be designed easily for extension of array because it has simple structure.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.135-138
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• 2004

Mobile phone antenna needs a small size and light weight for carrying and handling. In case of receiving a wide band TV signal, it would be difficult to obtain a good impedance matching between the antenna and the circuit due to a large capacitive reactance of antenna. Buffer amplifier was established on the teflon( ${\varepsilon}_r=3.38$, h=20mils) substrate by using GaAs FET( CPY30 ) and Silicon RF Transistor( BFP540 ) produced by Infineon and experimented.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.981-983
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• 1998

In this paper, we present theoretical designs for a beam steering phased array antenna that uses a true time delay optical feeder. A variable true time delay is achieved by employing one tunable laser source and high dispersion fibers with different length. The wavelength tunable optical carrier propagation in a high-dipersion fiber realizes a true time delay, with the steering direction set by a single voltage controlling the wavelength. Beamsteering of a phased array antenna is obtained by controlling the tunable laser source. An employment of a high dispersion fiber response shows wide-band operation of beem steering antenna system.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.3
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• pp.138-145
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• 2008

In this paper, the waveguide slot array antenna which is capable of wide beam steering and dual polarization is designed for an X band synthetic aperture radar. In order to improve the restriction of beam steering range and to remove the butterfly lobes, a typical waveguide slot array antenna has been modified. To implement dual polarization, rod excited waveguide slot elements and ridge waveguide slot elements are alternately arranged. Location of slots, inclination of rod and offset distance of slots are determined on using array characteristic and conductance constant with radiating power on slots. The designed antenna is manufactured and measured with Near-filed measurement method.