Reference Standard
Mathematical error correction requires physical standards to establish a measurement reference plane for high frequency testing. When using a trl calibration substrate, the network analyzer removes cable and fixture parasitics from the final data set. This approach relies on the thru, reflect, isolation and line standards built into the board to define the electrical port.
Error Correction
Algorithm execution relies on the mathematical difference between a direct connection and a known length of transmission line. When using a trl calibration substrate, the measurement system first connects the thru standard to establish the baseline insertion loss and phase. Reflect standards then identify the source match and load match by providing a high degree of signal reflection.
After these steps, the line standard allows the system to calculate the characteristic impedance and propagation constant of the interconnects. This process shifts the measurement point from the instrument cables directly to the pads of the component under test. Accurate calibration ensures that the performance of the device is not masked by the properties of the test fixture itself.
Material Quality
Dimensional stability of the substrate is paramount for accuracy at frequencies above ten gigahertz. Ceramic or high frequency laminates are used to minimize thermal drift.
