2012 Volume 9 Issue 22 Pages 1762-1774
Recently, compact wireless modules are very significant parts for multi-band wireless systems such as mobile phones and compact personal computers. A low temperature co-fired ceramic (LTCC) substrate which has embedded passive components is effective technology for producing the compact modules, because this substrate is suitable for a multilayer structure and is also a low dielectric loss and a low conductor loss. Therefore, a lot of multi-band wireless systems use this technology. In the radio frequency circuits of the multi-band wireless systems, a multiplexer is one of the most important passive circuits, in order to achieve both a compact size and high performances. In this paper, we report the technology of the compact multiplexer modules using the LTCC substrate. This paper especially focuses on the multiplexer for ultra-wideband wireless systems. The multiplexer which is suitable for narrow band wireless systems is also described.