Home   3 Pole Band Pass Filter Topologies

This shows 70 possible ways to construct a 3 pole band pass filter using inductors, capacitors, and transmission line elements. The best topology depends on the bandwidth and center frequency of the filter, and the parts available. For example, the topologies employing transmission lines are obviously better suited for designs well above 1 GHz. Some of these work better than others if the filter needs to be tuned with varactor diodes, and need to keep the voltage swing across the varactor within limits. Still others employ extra resonators to create a sharp null at some frequency. There is a huge number of good ways to design band pass filters.

Most of these topologies are available in the Iowa Hills RF Filter Designer.

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