Waveguide water loads manufactured by Cobham Sensor Systems (Exeter NH) offer high average power handling, low VSWR and rugged construction designed for severe environmental conditions. These terminations utilize a ceramic block window as a dielectric step transformer to match the impedance of the water to that of the waveguide. These miniature loads have very high power capability. However, bandwidths are limited to 12 to 16 percent and the inlet coolant temperature range is approx. 40°C. Typically, these terminations are designed for water input temperatures between 20°C and 40°C.
Cobham Sensor Systems also offers dry terminations that are manufactured by either welding the waveguide around the RF attenuator or by high temperature bonding into the finned or unfinned sections of waveguide. Extensive engineering effort has gone into the design of Cobham's dry loads to ensure an even loss distribution over the length of the load, thus eliminating hot spots and prolonging the life of the component.
