Patent ID: 8907742

Claim:
A radio frequency (RF) filter, configured to output RF energy at a center frequency wavelength λ, the RF filter comprising: a multi-cavity metallic housing, the housing comprising a plurality of walls that define a plurality of resonator cavities; the walls between adjacent sequential resonator cavities having openings configured to couple adjacent sequential resonator cavities; at least one electrically conductive coupling probe disposed through an aperture of a wall between a first resonator cavity and a second resonator cavity, the coupling probe having opposite probe ends comprising a first probe end extending into the first resonator cavity and a second probe end extending into the second resonator cavity so as to couple RF energy between the first resonator cavity and the second resonator cavity; and an electrostatic discharge (ESD) protective arrangement, the ESD protective arrangement being configured to provide a low resistance electrical path by way of an electrically conductive post extending from a central portion of the coupling probe to the metallic housing; wherein: the electrically conductive post is disposed between and external to the first resonator cavity and the second resonator cavity and is configured to provide a high impedance, between the coupling probe and the metallic housing, to RF energy having wavelengths proximate to λ.