The Bolovac and Its Applications

The Bolovac is a novel device for the standardization and measurement of TEM voltage, current, and power from below 1 MHz through 18 GHz (potentially through 36 GHz). It can be used for attentuation measurement and as a superior impedance termination at all the above-mentioned frequencies. To date it is the first and only practical means of calibrating microwave current indicators and of evaluating oscilloscopes displaying 25-ps or shorter risetime pulses. It is felt that application of the Bolovac will radically improve power measurements. It reduces the problems arising from mismatch-error uncertainties, one of the major present sources of concem in power measurement; measurement of complex reflection coefficients; complex computations; use of error-limit charts; and measurement of effective efficiency and calibration factors. Its application should radically increase optimum accuracy and measurement-time efficiency in calibration facilities outside the National Bureau of Standards. The Bolovac together with an RF generator can be used as a source of known voltage. It can also be used as an absorption power meter. It needs no RF calibration. It has a range as high as 40 dB depending on the desired precision and on whether one or more sensors (special bolometric disks) are used. Voltages down to 0.1 volt with accuracies of 0.5 percent and better (and corresponding power in 50-ohm systems) have been measured. The paper describes the general features and application of the Bolovac and lists references to more comprehensive papers on the subject.