Small form-factor integrated balun with complex impedance matching

In most of wireless communication systems, especially the front end modules, there are baluns connecting active circuits (e.g., PA and LNA) . Commercially available baluns are made in some fixed impedance ratios (50:50 ohm, 50:100 ohm, etc.), which usually do not match the input or output impedance (usually in complex) of active devices. We have developed a magnetically coupled balun which has both balun and matching functions using Silicon Integrated Passive Device (IPD) technology. The size of the balun is 1.2 x 1.0 x 0.4 mm³, which is by far the smallest balun with complex impedance matching, to the best of our knowledge. Prototypes are made and measured. Good agreement has been achieved between designed and probed data. This small form-factor balun can be well used in SiP applications to reduce SMD components count and package sizes.