Joubert, JohanOdendaal, J.W. (Johann Wilhelm)2015-09-152015-09-152015-11Joubert, J & Odendaal, JW 2015, 'Design of compact planar rat-race and branch-line hybrid couplers using polar curves', Microwave and Optical Technology Letters, vol. 57, no. 11, pp. 2637-2640.0895-2477 (print)1098-2760 (online)10.1002/mop.29397http://hdl.handle.net/2263/49845An approach where polar curves are used to miniaturize hybrid couplers is presented. The design of such couplers can be done with the optimization of a few parameters using full-wave analysis software. The results show similar or better electrical performance for a rat-race and branch-line coupler with respectively a 75% and 50% size reduction.en© 2015 Wiley Periodicals, Inc. This is the pre-peer reviewed version of the following article : Design of compact planar rat-race and branch-line hybrid couplers using polar curves, Microwave and Optical Technology Letters, vol. 57, no. 11, pp. 2637-2640, 2015. doi : 10.1002/mop.29397. The definite version is available at : http://onlinelibrary.wiley.comjournal/10.1002/(ISSN)1098-2760.Hybrid couplerRat-race couplerBranch-line couplerPolar curveCompact couplerPostprint Article