FIG. 2A illustrates an example of the filtering/coupling member 118, according to various implementations. As shown, filtering/coupling member 118 can be formed in a generally-cylindrical shape with increasing outer diameters 202, 204, and 206. The coupling/filtering member 118 can be hollow, forming a cavity 207 therein. The coupling/filtering member 118 can also include slots 208 proximal to an axial end thereof. The slots 208 may be configured to receive and hold a PCB assembly (e.g., PCB 120) stable, for example, to prevent such PCB assembly from rotating freely in the cavity 207 with respect to the filter/coupling member 118, or to be used as a ground contact for the PCB assembly.