No abstract

Satellite communications are used intensively today. Separating the different frequency channels requires high selectivity. Up to now, this high selectivity has been achieved by using circular filters placed in circular waveguides. However, circular waveguides require a complicated design process and are difficult to manufacture. In this article, a filtering method based on rectangular geometry and using the higher mode is presented. The synthesis procedure and its practical equivalent circuit are shown to create independent zeros to the right and/or left of the passband. To validate this new concept of filtering and the corresponding synthesis, applications on TE 10 /TE 30 in-line rectangular filters are presented. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE 15: 241-248, 2005.

This article presents a study of ladder-lattice bulk acoustic wave (BAW) filters. First, a review of BAW technology and filters topologies is addressed. Next, a mixed ladderlattice BAW filter for application on W-CDMA reception front-ends (2.11-2.17 GHz) is presented. An improved solidly mounted resonators (SMR) technology was used for the filter implementation. The filter synthesis methodology is briefly described. Layout guidelines are discussed enabling an optimized filter design. The filter on-wafer measurement results are as follows: 23.55 dB of insertion loss, 28.7 dB of return loss, an isolation higher than 247 dB at the transmission band (1.92-1.98 GHz) and an improved selectivity (230 dB at 2.14 GHz 6 60 MHz). Therefore, we can observe that the mixed topology combines the advantages of ladder and lattice networks, having very steep responses and an improved isolation at undesired bands.