Calibration of guided microwave quantities

We calibrate the fundamental microwave quantities power, impedance, reflection coefficient, attenuation, S-parameters, effective source impedance and frequency.
Power sensors

Calibration setup for power sensors

For power sensors one commonly calibrates the calibration factor and the reflection coefficient. We calibrate power sensors with type-N, 3.5 mm, and 2.92 mm connectors from 45 MHz to 40 GHz.
The calibration factor is determined by comparing measurements with our working standards which in their turn are traceable to microcalorimeters. The reflection coefficient is calibrated with a network analyzer.

Impedance standards

The most common impedance standards are Short, Open, and Load which are calibrated with a network analyzer.

 

Impedance standards

The impedance (or reflection coefficient) of the standard is determined through comparison with coaxial airlines. The airlines have an impedance that is calculable from their geometrical dimensions. We calibrate impedance standards with type-N, 3.5 mm, and 2.92 mm connectors from 45 MHz to 40 GHz.

Attenuation standards

There are two types of attenuation standards: fixed attenuators and step attenuators. For fixed attenuators we calibrate the complete set of two port S-parameters and for step attenuators we calibrate the incremental attenuation which is the ratio between the step and the zero position. In both cases we use a network analyzer for the calibration. We calibrate attenuation standards with type-N, 3.5 mm, and 2.92 mm connectors from 45 MHz to 40 GHz. 

S-parameters

Step attenuator

Reflection coefficiens, one and two port S-parameters are also calibrated with a network analyzer. We calibrate S-parameters for objects with type-N, 3.5 mm, and 2.92 mm connectors from 45 MHz to 40 GHz.

Power splitters

Power splitters are common for leveling of signal generators. This gives a stabilized source with an effective source impedance defined by one splitter arm. This effective source impedance (or effective source match) is calibrated with a network analyzer. We calibrate effective source impedances of objects with type-N, 3.5 mm, and 2.92 mm connectors from 45 MHz to 40 GHz.

Frequency counters

Frequency counters are calibrated by comparing the frequency of an injected signal with the valued measured by the frequency counter.

The injected signal is synchronized with our atomic clocks. If the internal reference (usually 10 MHz) of the counter is accessible it can be directly calibrated. We calibrate frequency counters up to 46 GHz.

SP Technical Research Institute of Sweden, Box 857, SE-501 15 Borås Phone +46 10-516 50 00, E-mail info@sp.se