• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1661-1666
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• 2014

In this paper, a compact planar ultra wideband (UWB, 3.1~10.6GHz) multiple-input multiple-output (MIMO) antenna is proposed. This antenna consists of two monopole planar UWB antennas and T-shaped stub decoupling between two antennas. The T-shaped stub improve the isolation characteristic at the wide band. The evolution strategy(ES) algorithm is employed to optimized design. As a result, optimized antenna has a return loss less than -10dB and the isolation less than -15dB from 3.1GHz to 10.6GHz. During the optimization process, the antenna gain is enhanced at lower band and the envelope correlation coefficient(ECC) is lower than 0.003.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.459-462
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• 2008

This paper describes the design of single body type repeater antenna for isolation enhancement between donor and receptor antennas. The antenna system consists of cavity, triangular patch antenna and cavity reflector. The antenna satisfies return-loss and isolation specifications in the desired band while the broadside gain is a little bit short from the spec.

• Journal of electromagnetic engineering and science
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• v.16 no.4
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• pp.206-209
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• 2016

This letter proposes a reconfigurable directional coupler that uses a variable impedance mismatch reflector to achieve high isolation characteristics in the antenna front end. The reconfigurable coupler consists of a directional coupler and a single-pole four-throw (SP4T) switch with different load impedances as a variable load mismatch reflector. Selection of the load impedance by the reflector allows cancellation of the reflected signal due to antenna load mismatch and the leakage from the input to isolation port of the directional coupler, resulting in high isolation characteristics. The performance of the proposed architecture in separating the received (Rx) signal from the transmitted (Tx) signal in the antenna front end was verified by implementing and testing the reconfigurable coupler at 917 MHz for UHF radio-frequency identification (RFID) applications. The proposed reconfigurable directional coupler showed an improvement in the isolation characteristics of more than 20 dB at the operation frequency band.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.465-470
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• 2002

A novel phased array antenna system for space-borne polarimetric SAR is proposed and completed in this paper.The antenna system assures polarimetric and multi-mode capability of SAR. It has broadband, high polarization isolation and high port to port isolation. The antenna system is composed of broadband polarimetric microstrip antenna, T/R modules and multifunction beam controller nit. The polarimetric microstrip antenna has more than 100MHz bandwidth at L-band with -30dB polarization isolation and high port to port isolation. The microstrip element and T/R module's structure and characteristics, the subarray's performances measuring results are presented in detail in this paper. A design scheme on beam controller of the phased array antenna is also proposed and completed, which is based on Digital Signal Processing (DSP) chip -TMS320F206. This beam controller unit has small size and high reliability compared with general beam controller. In addition, the multifunction beam controller unit can acquire and then send the T/R module's working states to detection system in real time.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.8
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• pp.865-871
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• 2010

A compact dual-band(IEEE 802.11b: 2.4~2.5 GHz, 11a: 5.15~5.825 GHz) 2-channel MIMO antenna for PMP applications is presented. The proposed antenna is composed of a planar inverted F-shape antenna(PIFA) operating at 2 GHz band and a loop antenna operating at 5 GHz band. The proposed antenna is orthogonally arranged at the edge of the ground plane for polarization and pattern diversities with excellent isolation characteristics. The two PIFA antennas operating 2 GHz have connecting line($\lambda_g$/4) face to the feed point for high isolation and low correlation at 2 GHz band. The two loop antennas connected each other in the bottom side to improve the isolation at 5 GHz band. The proposed antenna has a sufficient gain in WLAN service band and is compact sized for the portable media player (PMP) applications.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.265-270
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• 2005

In this paper, four-element MIMO(Multi-Input Multi-Output) antenna operating at 5.2GHz and 5.8GHz is proposed. Each antenna element is fabricated by using inverted-L type and the isolation characteristic among antenna elements is adjusted by the distance between radiation element and ground. The designed array antenna has the impedance bandwidth at 5.15$\sim$5.35 and 5.725$\sim$5.825GHz for VSWR$\leq$3 and the isolation characteristic less than -20dB at same frequency.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.108-116
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• 2018

In this paper, a method of designing a Vivaldi type phased array antenna (PAA) which operates at S-band (2.8-3.3 GHz) is presented. The presented antenna uses broadside coupled split ring resonators (BC-SRRs) for high isolation, wide field of view, and good active S-parameter characteristics. As an example, we design a $1{\times}8$ array antenna with various BC-SRR structures using theory and EM simulations. The antenna is fabricated and measured to verify the design. With the BC-SRR implemented between the two radiating elements, the isolation is shown to be enhanced by 6 dB, up to 23 dB. The scan angle is shown to be within ${\pm}53^{\circ}$ based on a -10 dB active reflection coefficient. The operation of the scan angle is possible within ${\pm}60^{\circ}$ with a little larger reflection coefficient (-7 dB to -8 dB). The proposed design with BC-SRRs is expected to be useful for PAA applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.661-668
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• 2012

In this paper, a dual-fed small ICS repeater antenna with high isolation is designed, fabricated, and measured. Bandwidth and gain are optimized by changing the stub lengths near main patch and power divider, and also by changing the size of parasitic patch. To improve the isolation characteristic of the antenna, a dual-feeding method is applied in designing the antenna. The fabricated antenna has a VSWR less than 2, a gain over 7 dBi, and an isolation between the donor and the server antennas less than -65 dB from 1,920~2,170 MHz for 3G mobile communication.

• 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.

• ETRI Journal
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• v.34 no.1
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• pp.114-117
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• 2012

A small-sized ($15mm{\times}30mm$) planar monopole MIMO antenna that offers high-isolation performance is presented in this letter. The antenna is miniaturized using inductive coupling within a meander-line radiator and capacitive coupling between a radiator and an isolator. High isolation is achieved by a T-shaped stub attached to the ground plane between two radiators, which also contributes to the small size using a folded structure and the capacitive coupling with radiators. The proposed antenna operates for the WLAN band within 2.4 GHz to 2.483 GHz. The measured isolation (S21) is about -30 dB, and the envelope correlation coefficient is less than 0.1.