A new UWB (ultra wideband) BALUN/180° Power Divider employing the broadband characteristics of microstrip — slotline transition is reported. The reported BALUN shows a wide bandwidth of 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 results of the design as well as those of the frequency mixers and doublers utilizing the BALUN show potential for use in 5G sub-systems. Results from the realization of the BALUN on LTCC substrates show superior performance on LTCC/Ceramic substrate which makes miniaturization possible without the need for a tradeoff with performance. Simulations with substrates like sapphire have shown the capability of the design to hold good up to 130GHz.