Ultra wide band balun/180° power divider using microstrip-slotline-microstrip transition

A novel UWB (ultra wideband) BALUN/180° Power Divider utilizing the broadband characteristics of microstrip - slotline transition is reported. The measured operational frequency range of the BALUN on RO4003C substrate is 4GHz-45GHz, corresponding to a typical insertion loss of 4±1dB with an amplitude and phase imbalance of under ±1dB and ±7° respectively. Simulation and measurement of the design on LTCC substrates show reduced loss of around 3.5±1dB with amplitude and phase imbalance of under ±1dB and ±4° respectively, in addition to an increased operational frequency range of 8GHz-90GHz, and reduction in the physical dimensions to 3 mm × 8 mm. Simulations and initial measurement with sapphire substrate have shown the capability of the design to hold good up to 130 GHz.