An apparatus for converting a two-port vector network analyzer to an N-port vector network analyzer and for calibrating the N-port vector network analyzer includes a test set having a first port coupled to a first port of the two-port vector network analyzer, a second port coupled to a second port of the two-port vector network analyzer and N-ports. The test set includes a circuit that selectively couples one of the N-ports of the test set to the second port of the test set. The apparatus also includes a multi-state transfer standard having N-ports coupled, respectively, to the N-ports of the test set. The multi-state transfer standard provides, at each of the N-ports of the multi-state transfer standard, a plurality of conditions necessary to calibrate the two-port vector network analyzer.

Method and apparatus for providing and calibrating a multiport network analyzer

A system and method of calibrating an S parameter measurement instrument (10, 30) (such as a vector network analyzer) in which the number of calibrations required to fully characterize the error model of an n-port system is n/2 calibrations for an even number of ports and (n+1)/2 calibrations for an odd number of ports. Each test port (52-58) in the system is involved in at least one full calibration, thus n/2 test paths are fully calibrated. For each measured test path, the error terms of the applicable error model are calculated. These error terms are then decoupled from the associated test path into error parameters that are localized to the individual test ports of the test path. Having localized the error parameters, the error model for each test port can then be treated independently from the other test ports. The error terms for the test paths that are not calibrated are then constructed using the localized error parameters for the individual test ports.

Scattering parameter calibration system and method

A method and system for calibrating a test system and a vector network analyzer use models of unknown calibration standards for a standards-based calibration. The models are selected for the unknown standards and performance data for each different calibration standard of the set are measured by the test system. The performance data is used to optimize the models by adjusting element values of constituent elements of the models. The optimized models are used to calibrate the test system such that the test system corrects for any imperfections in performance measurements taken of a device under test measured by the calibrated test system. The present invention further can correct for affects of a test fixture in device under test measurements. The method can also determine calibration coefficients for unknown calibration standards by extracting the calibration coefficients from the optimized models.

Calibrating a test system using unknown standards

An error correction method improves measurement accuracy of a vector network analyzer by reducing reflection measurement errors for a broad class of devices, such as filters, switches, cables, couplers, attenuators, and other passive devices tested by vector network analyzers (VNAs) that are reciprocal, having a forward transmission coefficient S 21 and a reverse transmission coefficient S 12 that are equal. Errors due to impedance mismatches at the load port of a transmission/reflection (T/R) test set are corrected without impacting the measurement speed of the VNA. The source port of the T/R test set is calibrated and a reflection measurement is performed while an impedance matched thruline standard of known electrical length is coupled between the source port and load port of the T/R test set. The reflection measurement is corrected for the electrical length of the thruline standard to obtain a reflection measurement of the load port of the T/R test set. Then, the transmission and reflection characteristics of the DUT are measured. The reciprocity of the DUT and the reflection measurement of the load port are used to extract the actual input reflection coefficient of the DUT.

Error correction method for reflection measurements of reciprocal devices in vector network analyzers

A high-precision, multi-port compatible, relative correction method and apparatus for correcting measurement errors covering an increase in the number of ports of a non-coaxial electronic component, in which a relative correction adapter 31 is provided that is formed of a two-port network connected to each port of a production test fixture 5 B adjacent to a measurement apparatus. The relative correction adapter has a characteristic that modifies the electrical characteristics generated by the production test fixture 5 B having an electronic component under test mounted thereon into electrical characteristics generated by a standard test fixture 5 A having the electronic component under test mounted thereon. An error factor of the relative correction adapter 31 is identified from a standard test fixture measurement value and a production test fixture measurement value of a correction data acquisition specimen 11 B. A production test fixture measurement value of the electronic component under test 11 A is corrected with the error factor of the relative correction adapter 31 to thereby obtain the standard test fixture measurement value of the electronic component under test 11 A which is assumed to be obtained when the electronic component under test 11 A.

Method of correcting measurement error and electronic component characteristic measurement apparatus

A method calibrates a network analyzer having two test ports and at least four measuring locations by successive measurement of the transmission and reflection parameters at three calibration standards successively connected in arbitrary sequence between the two test ports according to the seven-term principle. A first calibration measurement is implemented at an electrical line whose characteristic impedance is known and whose electrical propagation constant may be unknown and complex. Second and third calibration measurements are then respectively implemented at a two-port that is connected between the test ports and is constructed of concentrated components. The electrical propagation constant of the line and correction values that are taken into consideration in following object measurements are calculated from these measured values.

Method for calibrating a network analyzer according to the seven-term principle

In order to calibrate a network analyser, calibration measurements are carried out one after another in any desired sequence on three different calibration standards connected between the two measurement ports. In this case, a double port is used as the first calibration standard of which all the complex scatter parameters are known, this being, for example, carried out by direct connection of the two measurement gates. As the second calibration standard, use is made of a damping element having arbitrary transmission but known reflexion. As the third calibration standard, use is preferably made of a double port which has reflexion which is arbitrary but equal on both sides and different from the reflexion of the second calibration standard.

Method for calibrating a network analyser

The patent application relates to methods for establishing the complex measuring capability of network analysers operating in a homodyne mode. Both one-port and two-port measuring devices are treated in which the signal is detected by means of a linear mixing process. Using the proposed methods, it is possible to eliminate the defect of the homodyne detection process that it does not supply any direct information on amplitude and phase of the measured signal, by means of measuring arbitrary unknown standards. The required number of different unknown standards depends, inter alia, on the complexity of the measuring device used. One of the proposed methods operates without any standard.

Method for establishing the complex measuring capability of homodyne network analysers

The frequency synthesiser includes a phase-regulated oscillator (1), coupled to a phase detector (2) via a frequency divider (3) with a whole number division ratio (N). An output frequency (fi) is provided which is compared in phase with a reference frequency (fr), the feedback loop between the output of the phase detector and the control input of the oscillator contains a loop filter (4). The frequency divider division ratio is determined by a control circuit (7), with periodic switching of the division ratio for minimising phase noise in the oscillator output signal (fo). The control circuit output signal is obtained by adding a whole number component (P) of the division ratio to a supplementary component. The component is provided by a chain circuit with a number of integrators with feedback weighting components, for simulating a fractional division ratio.

Frequency synthesiser using fractional frequency synthesis

The method involves connecting several calibration standards (4) in an optional sequence in succession to both measurement gates (1,2) instead of the measurement object (DUT). Error correction data derived from the resulting measurement values are used for correcting systematic errors during measurements with a measurement object connected. For a measurement arrangement for which the connection between the measurement gates and the measurement object or calibration standard can be represented as a reciprocal four-gate network, only four calibration measurements are performed on four optional, different calibration standards, whereby at least one of the calibration standards transmits and at least one is reciprocal. The error correction values are computed in closed form from the measurement values using the 15-term error correction model, taking into account the reciprocity of the four-gate network.

Burkhard Prof Dr Ing Schiek

Papers

Method for calibrating a network analyzer according to the seven-term principle

Method for calibrating a network analyser

Method for establishing the complex measuring capability of homodyne network analysers

Frequency synthesiser using fractional frequency synthesis

Calibration method for vectorial network channel analyser