Abstract: Bias tees are provided that include a radio frequency (RF) transmission line. The bias tees include a dielectric material that is configured to provide a capacitance between the RF transmission line and ground. The bias tees include a high-frequency port, a common port, and a low-frequency port, and the RF transmission line is coupled between the common port and the low-frequency port.

Abstract: Filter devices are provided herein. In some embodiments, a filter device includes resonators and a cover that is attached by adhesive tape to a housing that includes the resonators. In some embodiments, the filter device includes a tuning cover that overlaps the resonators and has cleaning holes therein. Moreover, in some embodiments, the filter device includes a wall inside the housing between a first of the resonators and a second of the resonators, and an average thickness of the wall is 3.0 millimeters or thinner. Related methods of manufacturing filter devices are also provided.