The L-C lowpass is a direct application of synthesized prototypes and poses the fewest implementation difficulties of all filter structures. Ideally the same would be true for the distributed lowpass because the synthesis is based on the conversion of L-C filters. Also there is the potential for tighter tolerance on element values. However, difficulties are introduced by the unique characteristics of distributed elements such as reentrance, discontinuities and the realizable range of line impedance. In this chapter, distributed lowpass filters are studied. The effects of these limitations are considered along with potential methods of mitigating these difficulties.

Chapter Contents:

• 7.1 Overview
• 7.2 Stepped-Impedance All-Pole Lowpass
• 7.3 Response Sensitivity to Element Tolerance
• 7.4 Stepped-Impedance Measured Results
• 7.5 Stub-Line Lowpass
• 7.6 Elliptic Lowpass
• 7.7 Elliptic Lowpass Measured Responses
• 7.8 Element Collisions
• 7.9 References

Inspec keywords: low-pass filters

Other keywords: lowpass structures; L-C lowpass; distributed lowpass filters; filter structures

Subjects: Filters and other networks