A simple LTCC balun for WLAN applications using left-handed (LH) transmission lines (TL)

Low profile LTCC balanced filter based on a lumped elements balun for WiMAX applications

“…Moreover, increasing the number of elements results in a higher insertion loss. It has been shown that the design with only 3 elements for each high-pass and low-pass arm ( Fig.1) is acceptable from the performance point of view [11]. There is no strict limitation for the height of the structure for the discrete component realization but in a highly-integrated front-end module the size of building blocks in z-direction is very constrained because SMT components such as amplifiers, switches, inductors and capacitors have to be placed on the top of LTCC structure and they occupy additional space.…”

Methods and design techniques for the miniaturization of an L-band System-on-Package receiver front-end

“…With about the same operating bandwidth of the loaded case, further miniaturization is possible if the entire balun is implemented with lumped elements [95]. Simplified networks can be realized with extremely small dimensions but they display even narrower bandwidth [96] or poor phase balance [97]. Moreover, simplified networks make it difficult to optimize the amplitude and phase balance simultaneously due to the reduced number of design variables [98].…”