This thesis proposes methodology to design a balun with imaginary impedance. Under given specification, including center frequency, size, output impedance, our methodology can be used to evaluate its feasibility of implementation using high-DK LTCC(Low Temperature Cofired Ceramic) process. We then extend the design to incorporate a filter, which can simplify the circuit to reduce the required components. An example of our design operating at 2.4 GHz is implemented. Its size is 1600¡Ñ800¡Ñ650 um3, showing significant miniature. The simulation and measurement results are shown to verify the effectiveness of our design.