volume | PIER Journals

Abstract

A planar wideband balun is proposed. The proposed balun consists of a novel slotline T-junction and three microstrip-slotline transitions. Similar to the principle of the E-plane waveguide T-junction, the slotline T-junction acts as a phase inverter. With the microstrip-slotline transition, the device employs microstrip as feedlines. The radiation loss of the slotline is reduced to improve the insertion loss by loading the slotline with a superstrate and adding via holes along the slotline. An experimental balun with a bandwidth of 128% from 2.2 GHz to 10 GHz is designed, fabricated, and measured for validation. The measured results have reasonable agreement with the simulated ones.

1. Zhang, Z.-Y., Y.-X. Guo, L. C. Ong, and M. Y. W. Chia, "A new planar Marchand balun," IEEE MTT-S Int. Microw. Symp. Dig., 1207-1210, June 2005, doi 10.1109/MWSYM.2005.1516893.

2. Zhang, W.-W., Y.-N. Liu, Y.-L. Wu, W.-M. Wang, M. Su, and J.-C. Gao, "A complex impedance-transforming coupled-line balun," Progress In Electromagnetics Research Letters, Vol. 48, 123-128, 2014.
doi:10.2528/PIERL14062402

3. Lin, C.-M., C.-C. Su, S.-H. Hung, and Y.-H. Wang, "A compact balun based on microstrip EBG cell and interdigital capacitor," Progress In Electromagnetics Research Letters, Vol. 12, 111-118, 2009.
doi:10.2528/PIERL09092904

4. Yeh, Z.-Y. and Y.-C. Chiang, "A miniature CPW balun constructed with length-reduced 3 dB couples and a short redundant transmission line," Progress In Electromagnetics Research, Vol. 117, 195-208, 2011.
doi:10.2528/PIER11041503

5. Lai, C.-H., Y.-T. Cheng, and T.-G. Ma, "An artificial-transmission-line-based miniaturized doubly balanced ring mixer," PIERS Online, Vol. 6, No. 4, 2010.
doi:10.2529/PIERS090907055749

6. Wu, P., J. R. Liu, and Q. Xue, "Wideband excitation technology of TE20 mode substrate integrated (SIW) and its applications," IEEE Trans. Microw. Theory Techn., Vol. 63, No. 6, 1863-1874, 2015, doi: 10.1109/TMTT.2015.2427808.
doi:10.1109/TMTT.2015.2427808

7. Zhang, Z. Y., Y. X. Guo, L. C. Ong, and M. Y. W. Chia, "A new wide-band planar balun on a single-layer PCB," IEEE Microw. Wireless Compon. Lett., Vol. 15, No. 6, 416-418, 2005, doi: 10.1109/LMWC.2005.850486.
doi:10.1109/LMWC.2005.850486

8. Liu, C. and W. Menzel, "Broadband via-free microstrip balun using metamaterial transmission lines," IEEE Microw. Wireless Compon. Lett., Vol. 18, No. 7, 437-439, 2008, doi: 10.1109/LMWC.2008.924913.
doi:10.1109/LMWC.2008.924913

9. Xu, H.-X., G.-M. Wang, X. Chen, and T.-P. Li, "Broadband balun using fully artificial fractal-shaped composite right/left handed transmission line," IEEE Microw. Wireless Compon. Lett., Vol. 22, No. 1, 16-18, 2012, doi: 10.1109/LMWC.2011.2173929.
doi:10.1109/LMWC.2011.2173929

10. Ang, K. S and Y. C. Leong, "Converting baluns into broad-band impedance-transforming 180 hybrids," IEEE Trans. Microw. Theory Tech., Vol. 50, No. 8, 1990-1995, 2002, doi: 10.1109/TMTT.2002.801353.
doi:10.1109/TMTT.2002.801353

11. Tseng, C.-H. and Y.-C. Hsiao, "A new broadband Marchand balun using slot-coupled microstrip lines," IEEE Microw. Wireless Compon. Lett., Vol. 20, No. 3, 157-159, 2010, doi: 10.1109/LMWC.2010.2040216.
doi:10.1109/LMWC.2010.2040216

12. Abbosh, A., "Planar ultra-wide band balun using coupled microstrip lines," Electron. Lett., Vol. 49, No. 9, 662-664, 2013, doi: 10.1049/el.2013.0922.
doi:10.1049/el.2013.0922

13. Gupta, K. C., R. Garg, I. Bahl, and P. Bhartia, Microstrip Lines and Slotlines, 2nd Ed., Artech House, Norwood, MA, Bostion London, England, 1996.

14. Ho, C. H., L. Fan, and K. Chan, "Ultra wide band slotline hybrid-ring couplers," IEEE MTT-S Int. Microw. Symp. Dig., 1175-1178, June 1992, doi 10.1109/MWSYM.1992.188206.

15. Knorr, J., "Slot-line transitions," IEEE Trans. Microw. Theory Tech., Vol. 22, No. 5, 548-554, 1974, doi: 10.1109/TMTT.1974.1128278.
doi:10.1109/TMTT.1974.1128278

16. Janaswamy, R. and D. H. Schaubert, "Characteristic impedance of a wide slotline on low-permittivity substrates," IEEE Trans. Microw. Theory Tech., Vol. 34, No. 8, 900-902, 1986, doi: 10.1109/TMTT.1986.1133465.
doi:10.1109/TMTT.1986.1133465

17. Chung, Y. S., C. Cheon, I. H. Park, and S. Y. Hahn, "Optimal design method for microwave device using time domain method and design sensitivity analysis ---Part I: FETD case," IEEE Trans. Magn., Vol. 37, No. 5, 3289-3293, September 2001.
doi:10.1109/20.952597

18. Che, W., K. Dong, D. Wang, and Y. L. Chow, "Analytical equivalence between substrate-integrated waveguide and rectangular waveguide," IET Microw. Antenna Propag., Vol. 2, No. 1, 35-41, February 2008.
doi:10.1049/iet-map:20060283

Dr. Ya-Li Yao

Dr. Fu-Shun Zhang

Dr. Min Liang

Dr. Mao-Ze Wang