• Journal of Advanced Navigation Technology
• /
• v.14 no.6
• /
• pp.817-823
• /
• 2010

Design of IPI feeding structure affecting the antenna gain improvement of mobile phone was investigated. IPI feeder which based on the T matching theory increase line current for internal antenna such as IFA. So IPI feeder makes higher radiation resistance, and also increases the gain with increasing radiation efficiency. To verify IPI feeding effect, feeder is applied to conventional CDMA/DCS dual band IFA. Measurement shows that IPI-IFA has 0.5 ~ 1.4[dBi] higher gain than conventional IFA at CDMA/DCS band. Resonant frequency did not change.

• Journal of Advanced Navigation Technology
• /
• v.13 no.5
• /
• pp.662-668
• /
• 2009

Design of IPI(Inverted PI) feeding internal antenna for the gain improvement of mobile phone was proposed. IPI feeding structure affects on both low radiation resistance of antenna and increase current for the internal antenna such as IFA(Inverted F Antenna). By these facts, antenna fed by IPI can get the gain improvement with increasing radiation efficiency. For the verification, we applied IPI feeding structure to conventional quad band IFA. Measurement shows that IPI-IFA has 0.3~2.0[dB] higher gain than conventional IFA on GSM/DCS/USPCS/WCDMA band.

• Parasites, Hosts and Diseases
• /
• v.34 no.2
• /
• pp.121-126
• /
• 1996

For the detection of Cwptospori,mum oocysts, fecal samples were collected from 201 calves which showed diarrhea. Among the 201 samples, 29 samples (14.4%) were positive for Cwptosporinium spry. by the DMSO-modified acid-fast stain (MAFS) , 23 samples (11.4%) were positive by commercial kit (Meridian Diagnostics, Cincinnati, Ohiol and 23 by the indirect immunofluorescence antibody (IFA )assay employing the monoclonal antibody (mAb C6). When tested by both IFA and MAFS, 20 fecal samples were positive for Cwptosporinium oocysts whereas 169 fecal samples were negative. If the MAFS is considered a standard method for oocyst detection, the IFA showed 69% of sensitivity and 98% of specificity. When tested by both IFA and commercial kit, 22 fecal samples were positive for Cwptospori,mum oocysts while 177 samples were negative. One sample tested by IFA was found to be false negative, when compared with the results by commercial kit. The sensitivity of IFA was calculated as high as 96%; the specificity as 99% and the predictive value was also 99%. In the present study, IFA employing the nAb C6 revealed that 23 samples (11.4%) were positive among the 201 calves showing diarrhea. Of 23 IFA positive samples, 4 samples (5%) showed cryptosporidial oocysts more than 105 OPG Therefore. it is concluded that the calves showing cryptosporidial oocysts more than 105 OPG in the feces were highly associated with clinical cryptosporidiosis.

• Korean Journal of Veterinary Research
• /
• v.32 no.4
• /
• pp.641-647
• /
• 1992

This study was conducted to determine the serum antibodies against toxoplasma in the artificially infected dogs, pet and street dogs by latex agglutination (LA) and indirect fluorescent antibody (IFA) test. LA test was carried out with commercial Toxo-MT kit (Eiken chemical Co.) and IFA test was carried out with rabbit-anti-dog IgG labelled with FITC (Cappel Co.) and toxo-antigen slides prepared in laboratory. The results obtained were as follows ; 1. Antibodies to Toxoplasma gondii in the artificially infected dogs were detected firstly at the Day 8 in IFA and Day 9 in LA test after inoculation. Positive antibody reactions by these tests were declined gradually afterward but maintained up to 12 weeks. 2. In LA test serum antibody titers in 310 test sera were shown as 10 cases(32%) in 1 : 32.5(1.0%) in 1 : 64, 4(1.3%) in 1 : 128 and 2(0.7%) in 1 : 256. In IFA test serum antibody titers 310 test sera were shown as 17 cases(5.5%) in 1 : 64, 8(2.6%) in 1 : 128 and 5(1.6%) in 1 : 256. 3. In the total of 310 sera from pet and street dogs toxoplasma antibody positive rates were 21 cases (6.8%) by LA and 30 cases (9.7%) by IFA test and the positive detection rates between these two groups by LA and IFA test were not significant(p<0.05). 4. In the total of 115 sera from pet dogs toxoplasma antibody positive rates were 12 cases(10.4%) by LA and 15(13.0%) by IFA test. And in the 195 street dogs the positive rates were 9 cases(4.6%) by LA and 15(7.7%) by IFA test. Also, the positive detection rates between these two groups by LA and IFA test were not significant(p<0.05). 5. Agreement of reactivity between LA and IFA test for 310 sera was 91.3% in total of 283 cases consisting of 12 cases(3.9%) of both LA and IFA positive and 271 cases(87.4%) of LA and IFA negative. 6. LA test was almostly equivalent to the IFA test in producibility and proved to be a simple tool for the screening of toxoplasma antibody in laboratory.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.4
• /
• pp.545-548
• /
• 2017

This study describes the design and implementation of IFA(Input Filter Assembly) for Digital Satellite Communication. The IFA unit for SHF band consists of coupler, LPF(Low Pass Filter) and input Filter. Through the pre-simulation analysis of space environment, the possibility of the malfunction of equipment minimized and we designed a reliable IFA through simulation for vibration analysis generated during the launch, and compared pre-simulation of main performance results to test results about main performances of IFA after production.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.10 no.4
• /
• pp.65-70
• /
• 2011

In this paper, we designed and implemented a PIFA(Planer Inverted F Antenna) and IFA(Inverted F Antenna) hybrid antenna for the data communication terminal such as smart phone. Studied hybrid antenna has multi-band characteristics by the simultaneous operation both PIFA and IFA under a feeding structure. VSWR measurement of implemented antenna was satisfied 3:1 over GSM900/USPCS/WCDMA band. Measured average gains and efficiencies were -2.19~-3.63 dBi and 43.31~60.33 % for the GSM900 band, and -2.16~-10.67 dBi and 8.56~60.78 % for the USPCS/WCDMA band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.30 no.1
• /
• pp.1-7
• /
• 2019

In this paper, a design technique using a bypass capacitor is proposed to improve the antenna efficiency of an inverted-F antenna (IFA) with a band stop matching circuit (BSMC). The proposed antenna operates in the LTE bands 26 and 5(814~ 894 MHz). The bandwidth of the IFA is expanded from 803~863 MHz to 800~888 MHz using the impedance change caused by the BSMC. To enhance the antenna efficiency in the expanded frequency band, the bypass capacitor is applied to the IFA with the BSMC. The bypass capacitor improves the efficiency of the antenna by reducing the current variation of the IFA with the BSMC. The proposed antenna has a bandwidth of 804~895 MHz and the antenna efficiency increases by more than 10 % in the extended frequency band by using the bypass capacitor.

• Korean Journal of Veterinary Research
• /
• v.38 no.2
• /
• pp.314-318
• /
• 1998

An establishment of effective control measures to PRRSV infection in swine industry depends on a sensitive and specific diagnosis to detect either viral antigen and/or antibodies to PRRSV. Several diagnostic methods are available to detect antibodies against PRRSV, including IPMA, IFA and ELISA tests have been successfully developed. Sensitivity of the indirect immunofluorescent assay in MA-104 cells using Korean field isolate PL96-1 was superior to that of VR-2332 and field isolate PL96-2. Sensitivity and specificity of the IFA test with PL96-1 were comparable to those of commercial ELISA test kit but ELISA test was more sensitive for the detection of declining antibodies to PRRSV in finishing pigs. In this study we concluded that IFA and ELISA test could be utilized to detect antibodies to PRRSV and the results generated from these two tests were comparable and there were no significant difference between these two tests.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.5
• /
• pp.203-208
• /
• 2014

In this paper, the antenna of a small active RFID for 433MHz is proposed, and the proposed antenna is a kind of built-in antenna, which uses IFA structure. The performance was improved by the change of the spacing between the feed point and short strip, inserting the meander line structure in a radiator, and varying the gap between the radiator and the ground plane in the proposed antenna. To confirm the characteristics of the antenna parameters, HFSS from ANSYS Inc. was used for the analysis. The frequency band of 433MHz Active RFID is from 433.67 to 434.17 MHz. There is a value of return loss less than -9.54 dB in 433MHz band of the active RFID, and the maximum antenna gain is -4.28dBi. The Jig size of the proposed antenna is $72{\times}44{\times}1mm$, and the size of the antenna area is $35.5{\times}19.5mm$. The result proved the possibility of the practical use on miniaturized 433MHz antenna using IFA structure that came from comparing and analyzing the measured and simulated data of the antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.4
• /
• pp.357-364
• /
• 2015

In this paper, we designed and implemented a PIFA(Planar Inverted F Antenna) + IFA(Inverted F Antenna) hybrid MIMO(Multi Input Multi Output) antenna for the hexa mobile communication service band. By the simultaneous operation both PIFA and IFA using the coupled feeding structure, we tried for application to modern mobile phones that have large ground size. A PIFA is applied to the ground area, and an IFA is applied to no ground small space on top of the phone. A diagonal fed MIMO antenna is implemented PCB embedded type without antenna carrier component. Implemented antenna on the bare board measured within 3 : 1 for VSWR under hexa mobile communication band as CDMA, GSM900, DCS, KPCS, USPCS, and WCDMA. Measured average gains and efficiencies were -5.19~-3.16 dBi and 30.27~48.26 % for the CDMA, GSM900 band, and -9.50~-5.19 dBi and 11.23~30.28 % for the DCS, KPCS, USPCS, WCDMA band. It's shown that studied antenna can be applied to the antenna for the modern mobile phone.