Accurate MM-wave-to-THz power measurements with large-area pyroelectric detectors

摘要

We present an improved method for measuring power at ~100 GHz and above using a large-area (5-mm diam) LiTaO3 pyroelectric detector. The pyroelectric element is packaged in a lid-free TO-5 can, which in turn is mated to one end of a 1/2-inch-diam brass tube whose opposite end is flared for improved coupling efficiency. This “light-pipe”-like arrangement is cross-calibrated against a thermistor-based waveguide Anritsu ML83A power sensor using a 104-GHz Gunn oscillator and precision attenuator. It also stabilizes the pyroelectric element against background (IR) radiation and air currents. The resulting power detector is useful in the ~10-nW-to-1-uW region where waveguide power sensors do not operate and free-space sensors like Golay cells and pyroelectrics have always been uncalibrated and unstable.