Two octaves bandwidth passive balun for the eleven feed for reflector antennas

A new two octaves bandwidth balun is presented in the paper, which has a bandwidth of 3-13 GHz with a very compact size, -10 dB input reflection coefficient, low ohmic loss and large common mode suppression. A new descrambler circuit for the 2-13 GHz Eleven feed has been designed by using the new baluns, reducing from 4 twin-wire ports to 2 single-ended ports, one per polarization. The reflection coefficient of the whole Eleven antenna with the new descrambling circuit is below -8 dB over the frequency range of 3-13 GHz. Further improvement of the bandwidth of the new balun will be emphasized in the future work