• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.5
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• pp.21-26
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• 2014

This paper proposes a frequency reconfigurable antenna which operates at not only LTE but also other currently serviced bands. The high band(1,710-2,170 MHz) performance was satisfied through PIFA structure, and the low band performance through the additional RF Switch by changing the state between SW1 and SW2. When the RF switch is SW1 state, the operation bandwidth is 782-907 MHz (GSM), and 738-861 MHz (LTE) at OFF state. The proposed antenna has a omni-directional radiation pattern and measured peak gains were 0.04-4.68 dBi at the SW1 state and 0.92-1.53 dBi at the SW2 state, respectively. Judging from the results, proposed reconfigurable antenna is expected to be applied to LTE-Advanced mobile terminals since the antenna shows an outstanding performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2270-2275
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• 2011

The sintering behavior and microwave properties of ferrite ($Ba_3Co_{2-2x}Zn_{2x}Fe_{24}O_{41}$ ceramics) were investigated for microwave applications. Also PIFA type antenna with ferrite was simulated. All samples were prepared by the solid state reaction method and sintered at $1350^{\circ}C$. All ceramics had relatively density above of 92% compare with theoretical density of $Ba_3Co_2Fe_{24}O_{41}$ ceramics. From the XRD pattens, the Z-type phase was existed as main phase in $Ba_3Co_{2-2x}Zn_{2x}Fe_{24}O_{41}$ ceramics. The permittivity and permeability of $Ba_3Co_{2-2x}Zn_{2x}Fe_{24}O_{41}$ ceramics were increased with Zn additions and decreased rapidly over frequency of 200~600 MHz. Several PIFA type antennas with ferrite and FR4 were simulated. All antenna structure had return loss of less than -10 dB at each resonant frequency. Simulated antenna using both ferrite and FR4 showed size reduction of 25% without a significant decrement of efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.572-575
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• 2007

In this paper, we proposed a internal antenna for Quad band for GSM/DCS/USPCS/WCDMA Handset. Antenna Structure is designed to PIFA type. Antenna planed two independence patterns to reduce the size for efficiency and used shoting pin and inverse seven_type slit. Also they miniaturized the antenna construction electronic length for duty. furthermore, they designed and producted the antena height for 5w and ground term for 40*80mm. It is because they have wondered the thickness of terminal. used of for reduce size efficiently. The radiation pattern characteristic of antenna is compared and analyzed E-plane and H-plane at 920MHz, 1800MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.19-24
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• 2014

In this paper, a multiband LTE antenna satisfying LTE octa-band is proposed. The proposed antenna consists of a modified PIFA structure and a folded monopole which has the height of 4 mm. Each parts operates at lower and upper LTE band. Measured bandwidth(6 dB return loss) was 118 MHz(870~988 MHz) at the lower band and 1,107 MHz(1,650~2,757 MHz) at the upper band. The proposed antenna has a omni-directional radiation pattern and measured peak gains were 3.21 dBi at the lower band and 4.19 dBi at the upper band, respectively. The proposed antenna is expected to be utilized for future LTE-advanced system.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.5
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• pp.98-104
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• 2006

In this parer, proposed a Miniature inverted F Antenna for Bluetooth applications using folded structure and confirm it through producing and measurement. The proposed antenna as PIFA is optimized the impedance matching and the radiation pattern by positioning of feed line and short line. This antenna is designed with Microwave Studio presented CST and the optimized antenna structure is fabricated. The optimized miniature antenna size is 17.3 * 6 * 0.8 mm, the measured return loss bandwidth is 220MHz at 2.45GHz, the radiation pattern is quasi omni, and the gain is -1 dBi. these results are similar to the simulation data. It is comparatively appropriate for Bluetooth system.

• International journal of advanced smart convergence
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• v.1 no.1
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• pp.1-5
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• 2012

We propose a structure for a multiple input multiple output antenna which has no space for isolation. The antenna operates in a frequency range of 2.4-2.48 GHz and can achieve a high channel capability as a Bluetooth antenna. The MIMO antenna consists of two planar inverted F antennas with symmetric structure. We designed the proposed antenna using HFSS simulator, and we designed the fabricated antenna using PCB fabricator. The MIMO antenna's isolation $S_{21}{\leq}-10dB$ and reflection coefficient $S_{11}{\leq}-20dB$. The proposed antenna's specification satisfies Bluetooth antenna's criteria and has more space than the existing MIMO antennas, which have space for isolation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1194-1199
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• 2006

In this paper, small printed antennas for MIMO applications are presented. The proposed antennas are based on PIFA structure which is a popular approach for miniaturization. The obtained antenna operates in IEEE802.11a band (5.15-5.35GHz) and has a planar structure which can be adopted for various potable applications. According to our simulation results, prototype antennas are manufactured and the isolation among the antenna elements are measured for MIMO applications. And we suggest a technique to improve isolation by adding a $\lambda$/4 slit between two antennas and investigate the results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.2
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• pp.161-166
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• 2009

In this paper, we propose the internal mobile antenna for TDMB and KPCS. The proposed antenna is made of different dielectric substrate and it has small size ($45{\times}8{\times}8\;mm$, about 2.8 cc) for mobile device. TDMB antenna is designed spiral structure that makes maximum current for each cell and KPCS antenna is PIFA that is usually used for internal antenna. In order to compensate length of resonance TDMB antenna has a large inductor above 100 nH. In this case, the inductor isolate KPCS signal at TDMB by cutting high frequency. Also the antenna has good isolation because TDMB radiator is parasitic element in KPCS band. We simulated the antenna by using CST microwave studio and measured performance of the antenna in anechoic chamber Proposed antenna has $-6{\sim}-14\;dBi$ gain for TDMB and $-3.5{\sim}-5\;dBi$ gain for KPCS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1270-1276
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• 2010

In this paper, Quad-Band small antenna for GSM850, GSM900, DCS1800, DCS1900 is designed and fabricated. The antenna achieved the size reduction of over 67.9 % than the conventional PIFA(Planar Inverted-F Antenna) by using a MD(Magneto-Dielectric) material. A simple feeding microstrip line is used to feed the antenna from a $50{\Omega}$ coaxial line, which is capacitively coupled to the grounded patch structure for broadband characteristics. The impedance bandwidth the proposed antenna shows good results as broadband characteristics of 1341 MHz (801 ~ 2142 MHz) in VSWR < 3 (${\leq}\;-6\;dB$) and the gain is -6.67 ~ 4.25 dBi in the operating frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.784-795
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• 2007

In this thesis, the Multi element antenna with wideband and enhanced gain characteristic is proposed to operate at both frequency range from 824 MHz to 896 11Hz for the CDMA and frequency range from 908.5 MHz to 914 MHz for the RFID band. The proposed antenna has tile size of $35{\times}15{\times}5mm^3$ in order to put it in the A model of S company and each element of the proposed antenna is folded to obtain the minimum size. To obtain the antenna with wideband and high gain characteristic, the radiator of the antenna is divided into 4 elements. As a result, bandwidth of the proposed antenna become broader and lower center frequency is appeared due to increased and lengthened current path. Moreover, the enhanced gain characteristic is verified because divided element structure that induct uniform current distribution can get increased antenna efficiency. To attain more uniform current distribution, modified structure of the feeding point that can deliver currents directly is designed. The antenna that alters the feeding structure has higher gain value. Each element is folded to increase the current paths considering the current directions to attain the miniaturization of the antenna. To measure the handset antenna, the handset case must be considered. Even though antenna is designed for predicted characteristic, the resonance frequency is shifted and antenna gain is deteriorated at predicted frequency while antenna is set in the handset case. 1.08 GHz of the resonant frequency is determined after frequency shift from 150 MHz to 200 MHz is confirmed and the maximum gain is measured as 3.1 dBi while antenna is not set in the handset. In case handset case is considered, the experimental results show that the impedance bandwidth for VSWR<2 is from 0.824 GHz to 0.936 GHz(110 MHz). This result appears that the proposed antenna can cover both CDMA and RFID band at once. The measured gain is from -3.4 dBi to -0.5 dBi and it has omni-directional pattern practically.