Double schottky-barrier diode power sensor

A theory of the double Schottky-barrier diode power sensor is developed. It is shown that, by using two such diodes in a voltage-doubling circuit, the otherwise serious effects of the presence of spurious second harmonics in the source can be almost eliminated if the diodes have almost identical ideality factors. The theory is tested experimentally, and very good agreement with the theoretical predictions is found. A simple approximate formula is given from which it is possible to estimate the extent to which second-harmonic errors are eliminated when the ideality factors are different. The effect of third-harmonic content in the source is also calculated, although, in this case, the double-diode circuit offers no improvement over a single diode. The voltage-doubling effect, although incidental to the main purpose of the work described, offers a useful additional advantage.