Design of high performance band-pass filters by using multi-layer thick-film technology

Inherent limitations of the microstrip technology tend to reduce the operating possibilities of the different classes of well-known integrated band-pass filters. By choosing an appropriate technological process, some of these problems can be solved efficiently. In this paper, we present two original examples of microstrip band-pass filters for which significant improvements have been observed by using multi-layer thick-film technology. Firstly, thanks to the high coupling level thus achieved, a wideband microstrip end-coupled band-pass filters is presented. Then, the advantages of that particular process are illustrated by improving the frequency bandwidth rejection of a parallel coupled lines filter. Specific software was developed, and associated models were implemented on an HP-MDS© system. Experimental results are compared with theoretical responses.