References

• 1. 1)
     • 3. Shum, K.M., Xue, Q., Chan, C.H.: ‘A novel microstrip ring hybrid incorporating a PBG cell’, IEEE Microw. Compon. Lett., 2001, 11, (6), pp. 258–260 (doi: 10.1109/7260.928931).
  2. 2)
     • 5. Eccleston, K.W., Ong, S.H.M.: ‘Compact planar microstrip line branch-line and rat-race couplers’, IEEE Trans. Microw. Theory Tech., 2003, 51, (10), pp. 2119–2125 (doi: 10.1109/TMTT.2003.817442).
  3. 3)
     • 4. Gu, J.Z., Sun, X.W.: ‘Miniaturization and harmonic suppression rat-race coupler using C-SCMRC resonators with distributive equivalent circuit’, IEEE Microw. Compon. Lett., 2005, 15, (12), pp. 880–882 (doi: 10.1109/LMWC.2005.859980).
  4. 4)
     • 1. Settaluri, R.K., Sundberg, G., Weisshaar, A., et al: ‘Compact folded line rat-race hybrid coupler’, IEEE Microw. Compon. Lett., 2000, 10, (2), pp. 61–63 (doi: 10.1109/75.843101).
  5. 5)
     • 9. Tseng, C.H., Chang, C.L.: ‘A rigorous design methodology for compact planar branch-line and rat-race couplers with asymmetrical T-structures’, IEEE Trans. Microw. Theory Tech., 2012, 60, (7), pp. 2085–2091 (doi: 10.1109/TMTT.2012.2195019).
  6. 6)
     • 12. Ghali, H., Moselhy, T.A.: ‘Miniaturized fractal rat-race, branch-line, and coupled-line hybrids’, IEEE Trans. Microw. Theory Tech., 2004, 52, (11), pp. 2513–2520 (doi: 10.1109/TMTT.2004.837154).
  7. 7)
     • 6. Nesic, D.: ‘Slow-wave EBG microstrip rat-race hybrid ring’, Electron. Lett., 2005, 41, (21), pp. 1181–1183 (doi: 10.1049/el:20052819).
  8. 8)
     • 8. Shao, W., He, J., Wang, B.-Z.: ‘Compact rat-race ring coupler with capacitor loading’, Microw. Opt. Technol. Lett., 2010, 52, (1), pp. 7–9 (doi: 10.1002/mop.24823).
  9. 9)
     • 7. Wang, J., Wang, B.-Z., Guo, Y.X., et al: ‘Compact slow-wave microstrip rat-race ring coupler’, Electron. Lett., 2007, 43, (2), pp. 111–113 (doi: 10.1049/el:20073191).