Electrical filters are critical elements in communications, navigation and radar systems. The steadily increasing use of bandwidth in communications systems and consequent increased usage of microwave frequencies has created a need for small, selective filters above 1 GHz. Conventional lumped element filters can be obtained up to several GHz, but are costly, requiring tedious individual alignment by highly skilled technicians. Planar structures offer the potential to eliminate or reduce alignment, and hence to reduce cost. The proposed program will develop methods for the design and manufacture of planar, or microstrip, filters requiring no tuning or which can be tuned automatically. A key element will be the development of accurate methods of circuit modeling. The work will include the development of algorithms for evaluation of internal filter component values from external measurements. Design studies will identify filter configurations most amenable to automatic tuning. Methods of tuning, which may include removal or addition of material, will be developed. This program will result in more cost-effective production of filters at microwave frequencies. Filters are often one the more expensive components in microwave systems. Lower cost filters will be a factor in the deployment of higher frequency systems such as LMDS, Direct Broadcast Satellite, Intelligent Vehicle Highway Systems, radar systems and guided smart weapons. The techniques to be developed will be applicable to volume production.
Keywords: Filter, Microstrip, Automated-Tune , Planar, Microwave, No-Tune
