Abstract:

A broadband microstrip line to slotline balun with band notched characteristic is proposed.A broad operating band can be obtained by using a quarter-wave impedance transformer of 2 steps.A notched band can be realized by inserting a quarter-wave open stub on to the open stub of microstrip.The simulated results show that the impedance bandwidth with reflection coefficients less than -10 dB and insert loss better than -1.8 dB covers 0.38~2 GHz except the notched band 1.25~1.46 GHz.

Key words: Balun;broadband;band notched;microstip;slotline