A simple microstrip-to-CPS transition using elliptical transmission line as an Ultra-Broadband Balun

A simple and low cost broadband microstrip-to-CPS transition using 180 degree phase offset ellipse transmission line has been investigated. From the theory analysis and numerical simulations, the two back-to-back microstrip-to-CPS transitions has better than 10 dB return loss bandwidth and less than 3 dB insertion loss bandwidth of 4.2 GHz and 3.4 GHz, respectively. The same to former studies, this uniplanar transmission lines transition should have many applications for feeding printed dipole/quasi-yagi antennas, UWB system, phased arrays, and integration with MIC or MMIC devices.