For comparison purposes, the resistors are measured using a 1A current source and a precision voltmeter (see Figure 6). This figure shows the results for the 1 calibration resistor.
Figure 6: A power supply with current limit set to 1.00A is connected to one side of the resistor and a precision voltmeter is connected to the other side of the resistor. These connections replicate the connections used for the VNA measurements.
The DC measurements of the three resistors are 1.08m, 2.14m, and 5.26m, respectively. The VNA measurements are within 10% (1 dB) for all three low value resistors using this simple 1 shunt calibration technique.
About the author
Steve Sandler is the founder and former CEO of Analytical Engineering, Inc., the predecessor of AEi Systems. He has over 30 years experience in the design and analysis of power conversion equipment for military and space applications. Mr. Sandler is also the CEO of Picotest.com, a company that distributes test equipment including the Signal Injector product line designed for testing linear and switching power supplies, a Test & Measurement World "Best in Test" Finalist.