volume | PIER Journals

Abstract

A design of a compact wideband harmonic suppressed rat-race coupler (RRC) is presented in this paper. The present coupler is obtained by replacing each quarter wave length transmission line of a conventional double section rat-race coupler with a triple stub M-shape unit. The M-shape unit with 3 stubs is used to enhance the bandwidth, suppress the harmonics, and reduce the size of the coupler. Design guidelines are established using the lossless transmission line model. Theoretical predictions are verified by fabricating a prototype coupler. The proposed double section RRC provides harmonic suppression up to seventh of operating frequency and 62.4% size reduction with wide bandwidth, which is useful for wireless communication systems.

1. Pozar, D. M., Microwave Engineering, 4th Ed., John Wiley & Sons, 2012.

2. Velidi, V. K., D. K. Pandey, and S. Sanyal, "Microstrip rat-race couplers with pre determined miniaturization and harmonic suppression," Wiley Microwave and Optical Technology Letters, Vol. 52, No. 1, 30-34, January 2010.
doi:10.1002/mop.24832

3. Velidi, V. K., M. K. Mandal, and A. Bhattacharya, "Uniplanar harmonic suppressed compact rat-race couplers," Wiley Microwave and Optical Technology Letters, Vol. 50, No. 11, 2812-2814, November 2008.
doi:10.1002/mop.23840

4. Mondal, P. and A. Chakrabarty, "Design of miniaturised branch line and rat-race hybrid couplers with harmonics suppression," IET Microwaves, Antennas & Propagation, Vol. 3, No. 1, 109-116, 2009.
doi:10.1049/iet-map:20070202

5. Gruszczynski, S. and K. Wincza, "Broadband rat-race couplers with coupled-line section and impedance transformers," IEEE Microwave Wireless Components Letters, Vol. 22, No. 1, 22-24, January 2012.
doi:10.1109/LMWC.2011.2177649

6. Kim, Y.-G., S.-Y. Song, and K. W. Kim, "A compact wideband ring coupler utilizing a pair of transitions for phase inversion," IEEE Microwave Wireless Components Letters, Vol. 21, No. 1, 25-27, January 2011.
doi:10.1109/LMWC.2010.2089438

7. Sorocki, J., I. Piekarz, K. Wincza, and S. Gruszczynski, "Bandwidth improvement of rat-race couplers having left-handed transmission line sections," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 24, No. 3, 341-347, May 2014.
doi:10.1002/mmce.20766

8. Taravati, S., "Miniaturized wide-band rat-race coupler," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 23, No. 6, 675-681, November 2013.
doi:10.1002/mmce.20703

9. Abbosh, A. M., "Planar out-of-phase power divider/combiner for wideband high power microwave applications," IEEE Transactions on Components, Packaging and Manufacturing Technology, Vol. 4, 465-471, August 2013.

10. Mung, S. W. Y. and W. S. Chan, "Wideband microstrip rat-race hybrid with via-swap phase inverter," Electronic Letters, Vol. 50, No. 2, 96-98, January 2014.
doi:10.1049/el.2013.3234

11. Clenet, M., A. Sharaiha, and Y. M. M. Antar, "A compact wide-band rat-race hybrid using microstrip lines," IEEE Microwave Wireless Components Letters, Vol. 19, No. 4, 191-193, April 2009.

12. Kumar, K. V. P. and S. S. Karthikeyan, "Highly compact wideband double-section rat-race hybrid with harmonic suppression using series and shunt stepped impedance transmission line," International Journal of Microwave and Wireless Technologies, Vol. 9, No. 4, 1-7, Cambridge University Press and the European Microwave Association, 2016.

13. Riaan, F. and J. Johan, "A broad band 180◦ hybrid ring coupler using a microstrip-to-slotline inverter," Wiley Microwave and Optical Technology Letters, Vol. 57, 2164-2168, 2015.
doi:10.1002/mop.29299

Dr. Vuppuloori Ravi Reddy

Dr. Vamsi Krishna Velidi

Dr. Bhima Prabhakara Rao