A new wide-band microstrip phase inverter is reported in this paper. Interdigital striplines, defected ground and via holes are used to obtain 180° phase shift. The structure is simple and can be realized with ordinary microwave integrated circuit (MIC) fabrication process. The bandwidth is enhanced largely. A lumped-element model of the phase shifter is devised. The fabricated phase inverter has a bandwidth of 105.6% (2.065-6.682 GHz), with 1 dB insertion loss and a phase deviation less than 10°.
2. Chiou, Y. C. , C. H. Tsai, J. S. Wu, and J.-T. Kuo, "Miniaturization design for planar hybrid ring couplers ," IEEE MTT-S International Microwave Workshop, 19-22, 2008.
3. Wang, T., Z. Ou, and K. Wu, "Experimental study of wideband uniplanar phase inverters for MIC's," IEEE MTT-S Int. Microwave Symp. Dig., 777-780, 1997.
4. Wang, T. and K.Wu, "Size-reduction and band-broadening design technique of uniplanar hybrid ring coupler using phase inverter for M(H)MIC's," IEEE Trans. Microwave Theory Tech., Vol. 47, 198-206, 1999.
5. Chang, C. Y. and C.-C. Yang, "A novel broad-band Chebyshev-response rat-race ring coupler," IEEE Trans. Microwave Theory Tech., Vol. 47, No. 4, 455-462, 1999.
6. Kao, , C. W. and C. H. Chen, "Novel uniplanar 180 hybrid-ring couplers with spiral-type phase inverters," IEEE Microwave and Guided Wave Letters, Vol. 10, No. 10, 412-414, 2000.
7. Mousavi, P. , R. R. Mansour, and M. Daneshmand, "A novel wide band 180-degree phase shift transition on multilayer substrates," IEEE MTT-S Int. Microwave Symp. Dig., 1887-1890, 2004.
8. Chi, C. H. and C. Y. Chang, "A compact wideband 1800 hybrid ring coupler using a novel interdigital CPS inverter," Proceedings of the 37th European Microwave Conference, 548-551, Munich, Germany, Oct. 2007.
9. Mo, T. T. , Q. Xue, and C. H. Chan, "A broadband compact microstrip rat-race hybrid using a novel CPW inverter," IEEE Trans. Microwave Theory Tech., Vol. 55, No. 1, 161-167, 2007.
10. Kim, J. H., D. W. Woo, G. Y. Jo, and W. S. Park, "Microstrip phase inverter using slotted ground," Antenna and Propagation Society International Symposium (APSURS), 1-4, 2010.
11. U-yen, K. , E. J. Wollack, J. Papapolymerou, and J. Laskar, "A Broadband planar magic-T using microstrip-slotline transitions," IEEE Trans. Microwave Theory Tech., Vol. 58, No. 1, 172-177, 2008.