Tunable Filters | PAR Electronics | Filters for the commercial 2 way market, MATV, FM broadcast, laboratory, marine industry, amateur radio, scanner and short wave listening enthusiasts
Figure 2 from Sub-octave-tunable microstrip notch filter | Semantic Scholar
Smiths Interconnect - Tunable Filter Products
Ranatec Tunable Band Reject Filter| RI 266| 450 MHz - 6000MHz