A Comprehensive Review on Microstrip Couplers
Structure, Design Method and Performance
In this work, several types of microstrip couplers are investigated in terms of structure, performance and design methods. These planar 4-ports passive devices transmit a signal through two different channels. Designers' competition has always been in miniaturizing and improving performance of couplers. Some couplers have been offered with a novel structure, which is a special feature. A high-performance coupler should have high isolation and low losses at both channels. The channels are usually overlapped so that the common port return loss in these channels should be low. Among the couplers, those with balanced amplitude and phase are more popular. The popular mathematical analysis methods are even/odd mode analysis, extracting the information from the ABCD matrix and analyzing the equivalent LC circuit of a simple resonator. According to the phase shift value, couplers are classified as 90º and correct multiples of 90º, where a microstrip 0º coupler can be used as a power divider. Some couplers have filtering and harmonic elimination features that are superior to other couplers. However, few designers paid attention to suppressing the harmonics. If the operating frequency is set in according to the type of application, the coupler becomes particularly valuable.ABCD Matrix
Abdulbari, A.A., Rahim, S.K.A., Aziz, M.Z.A.A., Tan, K.G., Noordin, N.K., and Nor, M.Z.M., 2021. New design of wideband microstrip branch line coupler using T-shape and open stub for 5G application. International Journal of Electrical and Computer Engineering, 11(2), pp.1346-1355.
Abouelnaga, T.G., and Mohra, A.S., 2017. Reconfigurable 3 6 dB novel branch line coupler. Open Journal of Antennas and Propagation, 5, pp.7-22.
Alhalabi, H., Issa, H., Pistono, E., Kaddour, D., Podevin, F., Abouchahine, S., and Ferrari, P., 2018. Miniaturized branch-line coupler based on slow-wave microstrip lines. International Journal of Microwave and Wireless Technologies, 10(10), pp.1-4.
Arriola, W.A., Lee, J.Y., and Kim, I.S., 2021. Wideband 3 dB branch line coupler based on λ/4 open circuited coupled lines. IEEE Microwave and Wireless Components Letters, 21(9), pp.486-488.
Chang, H., Lim, T., Dimitrov, K.C., and Lee, Y., 2022. Dual-band branch-line coupler based on crossed lines for arbitrary power-split ratios. Sensors, 22, pp. 5527.
Chen, C.C., Sim, C.Y.D., and Wu, Y.J., 2016. Miniaturised dual-band rat-race coupler with harmonic suppression using synthetic transmission line. Electronics Letters, 52(21), pp.1784-1786.
Chen, C.F., Huang, T.Y., Shen, T.M., and Wu, R.B., 2013. Design of miniaturized filtering power dividers for system-in-a-package. IEEE Transactions on Microwave Theory and Techniques, 3(10), pp.1663-1672.
Chi, P.L., 2012. Miniaturized ring coupler with arbitrary power divisions based on the composite right/left-handed transmission lines. Microwave and Wireless Component Letters, 22(4), pp.170-172.
Chiu, L., 2014. Wideband microstrip 90˚ hybrid coupler using high pass network. International Journal of Microwave Science and Technology, 2014, pp.1-6.
Dydyk, M., 1999. Microstrip directional couplers with ideal performance via single-element compensation. IEEE Transactions on Microwave Theory and Techniques, 47(6), pp.956-964.
Feng, W., Duan, X., Shi, Y., Zhou, X.Y., and Che, W., 2020. Dual-band branchline couplers with short/open-ended stubs. IEEE Transactions on Circuits and Systems II, 67(11), pp.2497-2501.
Hong, J.S., and Lancaster, M.J., 2001. Microstrip Filters for RF/Microwave Applications. John Wiley and Sons, Hoboken.
Jia, L., Zhang, L., and Zhang, C., 2020. A dual-band and wide-band branch-line coupler with a large frequency ratio. Microwave and Optical Technology Letters, 63(1), pp.146-151.
Kao, C.W., and Chen, C.H., 2000. Novel uniplanar 180° hybrid-ring couplers with spiral-type phase inverters. IEEE Microwave and Guided Wave Letters, 10(10), pp.412-414.
Khan, Z.B., Mehdi, G., and Zhao, H., 2019. Design of a compact hybrid branch line coupler with 2-D implementation of stepped impedance transmission lines of high impedance ratio for wide range of harmonic suppression. ACES Journal, 34(8), pp.1211-1218.
Kim, C.S., Kim, Y.T., Song, S.H., Jung, W.S., Kang, K.Y., Park, J.S., and Ahn, D., 2001. A Design of Microstrip Directional Coupler for High Directivity and Tight Coupling. In: Microwave Conference. European.
Kim, C.S., Lim, J.S., Kim, D.Y., and Ahn, D., 2004. Adesign of single and multisection microstrip directional coupler with the high directivity. IEEE MTT-S International Microwave Symposium Digest, 3, pp.1895-1898.
Kim, J.S., and Kong, K.B., 2010. Compact branch-line coupler for harmonic suppression. Progress in Electromagnetics Research, 16, pp.233-239.
Kumar, M., Islam, S.N., Sen, G., and Parui, S.K., 2020. Design of filtering directional coupler with improved performance. International Journal of RF and Microwave Computer Aided Engineering, 30(2), e22224.
Kumar, S., Tannous, C., and Danshin, T., 1995. A multisection broadband impedance transforming branch-line hybrid. IEEE Transactions on MicrowaveTheory and Techniques, 43(11), pp.2517-2523.
Lai, C.H., and Ma, T.G., 2013. Miniaturised rat-race coupler with second and third harmonic suppression using synthesised transmission lines. Electronics Letters, 49(22), pp.1394-1396.
Lalbakhsh, A., Mohamadpour, G., Roshani, S., Ami, M., Roshani, S., Sayem, A.S., Alibakhshikenari, M., and Koziel, S., 2021. Design of a compact planar transmission line for miniaturized rat-race coupler with harmonics suppression. IEEE Access, 9, pp.129207-129217.
Li, J.L., Qu, S.W., and Xue, Q., 2007. Microstrip directional coupler with flat coupling and high isolation. Electronics Letters, 43(4), pp.228-229.
Liou, C.Y., Wu, M.S., Yeh, J.C., Chueh, Y.Z., and Mao, S.G., 2009. A novel triple-band microstrip branch-line coupler with arbitrary operating frequencies. IEEE Microwave and Wireless Components Letters, 19(11), pp.683-685.
Maheswari, S., and Jayanthy, T., 2022. Design of compact branch-line coupler for Wi-max applications. International Journal of Microwave and Optical Technology, 17(1), pp.68-73.
March, S.L., 1982. Phase velocity compensation in parallel-coupled microstrip. IEEE MTT-S International Microwave Symposium Digest, 82(1), pp.410-412.
Mojarrad, S., and Basharat, H., 2015. Modified double box branch line coupler by utilizing quasi T-shape stub. International Journal of Innovative Science Engineering and Technology, 2(11), pp.390-393.
Nie, W., Xu, K.D., Zhou, M., Xie, L.B., and Yang, X.L., 2019. Compact narrow/wide band branch-line couplers with improved upper-stopband. (AEÜ) International Journal of Electronics and Communications, 98, pp.45-50.
Noori, L., and Rezaei, A., 2018. A microstrip hybrid coupler with wide stopband using symmetric structure for wireless applications. Journal of Microwaves Optoelectronics and Electromagnetic Applications, 17(1), pp.23-31.
Rezaei, A., Noori, L., and Hosseini, S.M., 2018. Novel microstrip branch-line coupler with low phase shift for WLANs. Analog Integrated Circuits and Signal Processing, 98, pp.377-383.
Roshani, S., Yahya, S.I., Roshani, S., Farahmand, A.H., and Hemmati, S., 2022. Design of a modified compact coupler with unwanted harmonics suppression for L-band applications. Electronics, 11(11), 1747.
Salehi, M., and Noori, L., 2014. Novel 2.4 GHz branch-line coupler using microstrip cells. Microwave and Optical Technology Letters, 56(9), pp.2110-2113.
Salehi, M.R., Noori, L., and Abiri, E., 2015. Novel tunable branch-line coupler for WLAN applications. Microwave and Optical Technology Letters, 57(5), pp.1081-1084.
Sanna, G., Montisci, G., Jin, Z., Fanti, A., and Casula, G.A., 2018. Design of a low-cost microstrip directional coupler with high coupling for a motion detection sensor. Electronics, 7(2), p.25.
Santiko, A.B., Saputera, Y.P., and Wahyu, Y., 2016. Design and Implementation of Three Branch Line Coupler at 3.0 GHz Frequency for S-Band Radar System. In: The 22nd Asia-Pacific Conference on Communications. IEEE, Indonesia, pp.315-318.
Shamsinejad, S., Soleimani, M., and Komjani, N., 2008. Novel enhanced and miniaturized 90° coupler for 3G EH mixers. Progress in Electromagnetics Research Letters, 3, pp.43-50.
Shi, J., Qiang, J., Xu, K., Wang, Z.B., Lin, L., Chen, J.X., Liu, W., and Zhang, X.Y., 2016. A balanced filtering branch-line coupler. IEEE Microwave and Wireless Components Letters, 26(2), pp.119-121.
Shukor, N.A.M., and Seman, N., 2016. Enhanced design of two-section microstrip-slot branch line coupler with the overlapped k/4 open circuited lines at ports. Wireless Personal Communications, 88(3), pp.467-478.
Shukor, N.A.M., and Seman, N., 2020. 5G planar branch line coupler design based on the analysis of dielectric constant, loss tangent and quality factor at high frequency. Scientific Reports, 10, 16115.
Smolarz, R., Wincza, K., and Gruszczynski, S., 2020. Chebyshev-response branch-line couplers with enhanced bandwidth and arbitrary coupling level. Electronics, 9(11), 1828.
Sun, K.O., Ho, S.J., Yen, C.C., and Weide, D., 2005. A compact branch-line coupler using discontinuous microstrip lines. IEEE Microwave and Wireless Components Letters, 15(8), pp.519-520.
Sun, P., Chen, Q., Han, R., and Lu, A.Z., 2019. Analysis and design of wideband 90◦ microstrip hybrid coupler. IEEE Access, 7, pp.186409-186416.
Tang, C.W., and Chen, M.G., 2009. Design of multipassband microstrip branchline couplers with open stubs. IEEE Transactions on Microwave Theory and Techniques, 57(1), pp.196-204.
Tang, C.W., Chen, M.G., Lin, Y.S., and Wu, J.W., 2006. Broadband microstrip branch-line coupler with defected ground structure. Electronics Letters, 42(25), pp.1458-1460.
Tang, C.W., Tseng, C.T., and Hsu, K.C., 2014. Design of wide passband microstrip branch-line couplers with multiple sections. IEEE Transactions on Components Packaging and Manufacturing Technology, 4(7), pp.1222-1227.
Tian, H., Chung, K.L., Liu, R., Dai, M., and Tang, W., 2019. Miniaturised quadrature hybrid coupler using composite planar transmission lines. Electronics Letters, 55(19), pp.1049-1051.
Tripathi, N., 2018. Review paper on microstrip directional coupler with high directivity. International Research Journal of Engineering and Technology (IRJET), 5(5), pp.4149-4152.
Velan, S., and Kanagasabai, M., 2016. Compact microstrip branch-line coupler with wideband quadrature phase balance. Microwave and Optical Technology Letters, 58(6), pp.1369-1374.
Wang, J., Wang, B.Z., Guo, Y.X., Ong, L.C., and Xiao, S., 2007. Acompact slowwave microstrip branch-line coupler with high performance. IEEE Microwave and Wireless Components Letters, 17(7), pp.501-503.
Yaduvanshi, B., and Bhatia, D., 2016. Stub-Based Design of Coupled Line Directional Couplers. In: 2016 International Conference on Micro-Electronics and Telecommunication Engineering, IEEE, Ghaziabad.
Zhang, H., and Zhang, Z., 2019. Miniaturized microstrip branch-line coupler with good harmonic suppression based on radial stub loaded resonators. Progress in Electromagnetics Research Letters, 87, pp.15-20.
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