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Analytical Modeling of Conventional and Miniaturization Three-Section Branch-Line Couplers
Kok Yeow You,Nadera AL-AREQI,Jaw Chung Chong,Kim Yee Lee,Ee Meng Cheng,Yeng Seng Lee 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2
Analytical modeling equations are proposed for the conventional and modified threesection branch-line couplers. The analytical equations are explicit and capable of determining the characteristic impedance of each branch line for the coupler at desired coupling level as well as the suitability of broadband S-parameters analysis. In addition, a bandwidth extension and miniaturization of three-section branch-line coupler using slow-wave and meandering line structures were designed. The modified coupler, which is able to operate within frequencies from 1.5 to 3.32 GHz has been fabricated, tested and compared. A bandwidth extension of 600 MHz and 53% reduced size of the modified coupler have been achieved compared to a conventional coupler. The modified coupler has roughly insertion loss and coupling of -4 dB and -3.2 dB, while the isolation and return loss, respectively less than -14 dB with fractional bandwidth of 77 %, as well as phase imbalances less than 2° over the operating bandwidth. Overall, the derived analytical model, simulation and measurement results demonstrated a good agreement.
Ee Meng Cheng,Zulkifly Abbas,Hasliza A Rahim @ Samsuddin,Kim Yee Lee,Kok Yeow You,Jumiah Hassan,Hishamuddin Zainuddin,Shing Fhan Khor 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.6
Finite difference analysis were applied to study the principle operation of monopole antenna for moisture determination in oil palm fruit at 2 GHz. The electromagnetic field interact with oil palm fruit on the interface between the antenna and oil palm fruit and cause a reflection. The reflection measurement is based on mismatch impedance or dielectric properties between two media. Reflection coefficient is used to quantify the level of reflection. The monopole antenna was made of RG405/U semi-rigid coaxial cable with an inner and outer diameter of 0.45 mm and 1.50 mm, respectively with 2.23 mm length of protruding conductor over 5.66 cm length of monopole antenna. This monopole antenna for moisture detection was compared with induced EMF method in terms of reflection coefficient at 2 GHz. The results show that the complex reflection coefficient measured using monopole antenna provides significant results to predict moisture content in oil palm fruit.
Analytical Modeling of Conventional and Miniaturization Three-Section Branch-Line Couplers
You, Kok Yeow,AL-AREQI, Nadera,Chong, Jaw Chung,Lee, Kim Yee,Cheng, Ee Meng,Lee, Yeng Seng The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2
Analytical modeling equations are proposed for the conventional and modified three-section branch-line couplers. The analytical equations are explicit and capable of determining the characteristic impedance of each branch line for the coupler at desired coupling level as well as the suitability of broadband S-parameters analysis. In addition, a bandwidth extension and miniaturization of three-section branch-line coupler using slow-wave and meandering line structures were designed. The modified coupler, which is able to operate within frequencies from 1.5 to 3.32 GHz has been fabricated, tested and compared. A bandwidth extension of 600 MHz and 53% reduced size of the modified coupler have been achieved compared to a conventional coupler. The modified coupler has roughly insertion loss and coupling of -4 dB and -3.2 dB, while the isolation and return loss, respectively less than -14 dB with fractional bandwidth of 77 %, as well as phase imbalances less than $2^{\circ}$ over the operating bandwidth. Overall, the derived analytical model, simulation and measurement results demonstrated a good agreement.