We often get asked about how wide a filter’s bandwidth can be made. Typical filter technologies are limited to approximately 75% BW or so. For applications where ultra-wide, multi-octave bandwidths are required, you would need more than an ordinary filter. The best filter choice for bandwidths in the 150% range would be a design utilizing Suspended Substrate Technology (SST).
SST is a printed board topology that utilizes a double-sided printed board between two ground planes with air dielectric traces that mirror the circuit printed on the board. Ultra-wide responses are realized by combining highpass and lowpass circuits to create filters and multiplexers.
Using SST, achieving passbands from 2 to 18 GHz or 18 to 40 GHz and beyond are entirely possible. If you have ultra-wide bandwidth requirements, please contact us, and we will show you how well SST will work for you.