Broad-Band Calorimeter for Precision Measurement of Millimeter- and Submillimeter-Wave Power

A millimeter-wave dry calorimeter has been developed for power levels of 0.1 to 100 mW. The estimated instrument error for power levels of 10-100 mW is less than 0.3 percent. The required time for final reading is only about 40 s, which makes the instrument very useful for general laboratory power measurement. The VSWR is less than 1.15 over the whole waveguide band 60-90 GHz. The construction is simple compared to other designs with comparable accuracy.