A digitally controlled wideband precision electronic attenuator

We have designed and fabricated a low cost digitally controlled precision broadband PIN diode attenuator that provides an accuracy of +/-0.06 dB from 500 MHz to 2.5 GHz. This represents an improvement by about a factor of 10 over commercially available existing PIN diode attenuators. In addition, it leads to the possibility of the development of low cost electronic fast response noise figure meters based on the Y-factor procedure for noise figure measurement with a noise figure measurement precision of +/- 0.1 dB. By placing a digitally controlled precision attenuator both before and after the device under test, the Y-meter provides the additional benefit of minimizing the effect of impedance mismatch on the measurement accuracy