Rf power sensor having improved linearity over greater dynamic range

Abstract

A radio frequency ('RF') power sensor providing RF signal power sensing with reduced dependency upon its input signal power level includes multiple series-connected diodes for detecting the power of an input RF signal and providing an output voltage representing that power. The multiple series-connected diodes couple the input node shunted by an input load resistor to the output node shunted by an output filter capacitor. Using multiple series-connected diodes results in reduced reverse bias voltages across the diodes (presented by the charged output filter capacitor), thereby increasing their junction capacitances. These increased junction capacitances, in turn, result in reduced fractional changes thereof (e.g. capacitance 'modulation') over changes in the input RF signal power. This reduction in fractional capacitance changes as a function of input signal power variations, further in turn, results in reduced input signal power dependency of the sensors' impedances and sensitivities. Therefore, the power detection performed by the diodes becomes more predictable, e.g. more linear, over a broader input RF signal power range.