• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1233-1239
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• 2008

In this paper we proposed a novel broadband printed monopole antenna for PCS/IMT-2000/WLAN terminals by widening current flow To compensate narrow bandwidth characteristics which is one of disadvantages of general printed monopole antenna, we add the patch of diamond shape and induce the current in various directions for acquiring broadband characteristics. And frequency characteristics is optimized with Various design parameters. The bandwidth of the realized antenna is $1.66{\sim}3.04\;GHz$(58.72 %) below the return loss of -10 dB which contain the required band-width of PCS/IMT-2000/WLAN band.

• Journal of Navigation and Port Research
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• v.38 no.4
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• pp.367-371
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• 2014

When the crew or passengers fall into the water due to marine accident of vessel, it is very important to rescue them quickly. In the case of marine accidents, most people in distress have been wearing a lifejacket, so if the GPS and Cospas-Sarsat communication module will be integrated within the lifejacket, it is easy to rescue them. In this paper, development of the dual band lifejacket-integrated antenna for GPS and Cospas-Sarsat communication is discussed. The antenna with the FR-4 substrate of 0.2mm thickness for flexibility was designed that it can be fitted close to the shoulder of the life jacket and operate at 1.575GHz and 406MHz. The GPS communication antenna was implemented with a ring-slot antenna having a circular polarized characteristic and a meander type linear polarized antenna is used as Cospas-Sarsat communication. The two antennas are fed by a single microstrip line and an open stub is used to minimize the mutual interference between the two antennas. The performance of the fabricated antenna attached to the life vest is confirmed by the measurement of the return loss at GPS and Cospas-Sarsat frequency bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.12
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• pp.1340-1350
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• 2009

The design and implementation of planar Active Phased Array Antenna System are described in this paper. This Antenna system operates at X-band with its bandwidth 10 % and dual polarization is realized using dual slot feeding microstrip patch antenna and SPDT(Single Pole Double Through) switch. Array Structure is $16\times16$ triangular lattice structure and each array is composed of TR(Transmit & Receive) module with more than 40 dBm power. Each TR module includes digital attenuator and phase shifter so that antenna beam can be electronically steered over a scan angle$({\pm}60^{\circ})$. Measurement of antenna pattern is conducted using a near field chamber and the results coincide with the expected beam pattern. From these results, it can be convinced that this antenna can be used with control of beam steering and beam shaping.

• Journal of the Korea Society of Computer and Information
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• v.27 no.3
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• pp.71-77
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• 2022

In this paper, we propose 1×2 array antenna with dual linear polarization characteristics for mmWave band operation. The proposed antenna is designed two microstirp feeding structure and FR-4 substrate, which is thickness 0.4 mm, and the dielectric constant is 4.3. The size of 1×2 array antenna is 2.33 mm×2.33 mm, and total size of array antenna is 13.0 mm×6.90 mm. From the fabrication and measurement results, bandwidths of 1.13 GHz (28.52~29.65 GHz) for port 1 and 1.08 GHz (28.45~29.53 GHz) for port 2 were obtained based on the impedance bandwidth. Cross polarization ratios are obtained from 7.68 dBi to 16.90 dBi in case of vertical polarization, and from 7.46 dBi to 15.97 dBi in case of horizontal polarization for input port 1, respectively. Also, cross polarization ratios are obtained from 8.59 dBi to 13.72 dBi in case of vertical polarization and from 9.03 dB to 14.0 dB in case of horizontal polarization for input port 2, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.165-171
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• 2004

In this paper, the modeling and design of high-Q multilayer passives have been investigated, and multilayer diplexer for GSM/DCS applications has been designed and fabricated using the passives. Modeling of a multilayer inductor was performed by the subsystems of distributed components, and using the modeling the optimal structures of the high-Q multilayer inductor could be designed by analyzing parasitics and couplings which affect their frequency characteristics. Multilayer diplexers for GSM/DCS applications have been designed and fabricated using LTCC technology. LPF for GSM band had the passband insertion loss of less than 0.55 dB, the return loss of more than 12 dB, and the isolation level of more than 26 dB. HPF for DCS band had the passband insertion loss of less than 0.82 dB, the return loss of more than 11 dB, and the isolation level of more than 38 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.475-485
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• 2010

This paper proposes a novel concept for a microstrip resonator that can function as a filter and as an antenna at the same time. The proposed structure consists of an outer ring, an open loop-type inner ring, a circular patch, and three ports. The frequencies where the proposed structure works as a filter and as an antenna, respectively, are determined primarily by the radius of the inner ring and the circular patch. The measured results show that, when the microstrip resonator operates as a filtering device, this filter has about 15.1 % bandwidth at the center frequency of 0.63 GHz and a minimum insertion loss of 1.5 dB within passband. There are three transmission zeros at 0.52 GHz, 1.14 GHz, and 2.22 GHz. In the upper stopband, cross coupling - taking place at the stub of the outer ring - and the open loop-type inner ring produce one transmission zero each. The circular patch generates the dual-mode property of the filter and another transmission zero, whose location can be easily adjusted by altering the size of the circular patch. The proposed structure works as an antenna at 2.7 GHz, showing a gain of 3.8 dBi. Compared to a conventional patch antenna, the proposed structure has a similar antenna gain. At the resonant frequencies of the filter and the antenna, high isolation(less than -25 dB) between the filter port and the antenna port can be obtained.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.5
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• pp.325-335
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• 2018

We herein present a study on the active phased array antenna for receiving satellite broadcasting that can electrically align its polarization to that of target transmitters in its moving condition or in the Skew angle arrangement of the broadcasting satellite receiver. Hence, we have developed an active phased array structure composed of the self-developed Vivaldi antenna and multifunction core (MFC) chip, receiving RF front end module, and control units. In particular, the new Vivaldi antenna designed in the Ku-band of 10.7 - 14.5 GHz to receive one desired polarization mode such as the horizontal or vertical by means of an MFC chip and other control units that can control the amplitude and phase of each antenna element. The test results verified that cross-polarization property is 20 dB or higher and the primary beam can be scanned clearly at approximately ${\pm}60^{\circ}$.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.1
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• pp.70-74
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• 2015

In this paper, we have illuminated the radiation modes of rectangular planar antennas to interpret the nature of the wideband characteristic upon which formulas for bandwidth prediction are presented. Rectangular planar antennas are being investigated by many researchers in virtue of relatively simple design and fabrication procedures to replace the cylindrical monopoles. But the design principle for rectangular planar antennas is still based on that of cylindrical monopoles, and the nature of the wideband characteristic and the formula to estimate the upper band frequency are not analyzed yet. In this research, we have shown the patterns of the radiation modes explaining the wideband characteristic and also proposed the upper band frequency with minor modification for the lower band frequency formula based on mode formation principles. Finally we have confirmed the validity of our results, within 10 % accuracy, by the application to some published results.

• Journal of IKEEE
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• v.16 no.4
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• pp.297-303
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• 2012

This paper proposes the effective design procedure for a broadband, double-ridged horn antenna for evaluating the performance of the RF energy harvesting system with a multi-band rectenna. Using multi-mode network analysis, the higher-mode scattering parameters of the transition and horn were acquired and applied to the antenna design, respectively. As a result, the computing time could be reduced and the calculated VSWR(voltage standing wave ratio) of the antenna was very similar to the analyzed result using fully electromagnetic simulation. And there was also good agreement between the simulated and measured results. The designed broadband antenna has a bandwidth of 660~6360 MHz and 6~13.7 dBi peak radiation gain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.328-334
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• 2012

This paper proposes a design technique of wide-band antenna for handy phone with 700 MHz LTE(Long Term Evolution) low frequency bandwidth. The proposed antenna based on the PIFA(Planar Inverted-F type Antenna) structure was designed and considered. In order to realize the wide bandwidth, a round structure which is able to control the electric path length of current and a branch line element which can be obtain the dual resonance characteristics were introduced in this design. As a result, It was realized about 95 MHz bandwidth in spite of very small space of $30{\times}34mm$ used for FR-4 substrate with relative permitivity of 4.4 at 700 MHz band. Measurement results of return loss, bandwidth and gain radiation pattern were agreed well with their calculation results.