Frequency selective load pull tuner and method
OwnerChristos Tsironisinventor
Life of this patent
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Abstract
An automatic, frequency selective microwave tuner, used for load pull transistor testing, is capable of generating independently controllable reflection factors, both in amplitude and phase, at several, harmonic or not, frequencies simultaneously. The tuner employs horizontally and vertically adjustable high Q resonant probes and replaces, when used in harmonic load pull set-ups, otherwise required combinations of wide-band tuners with harmonic rejection tuners or wide-band tuners and frequency discriminators (diplexers or triplexers).
Claims8
An electro-mechanical load pull tuner comprises a test port and an idle port, a slotted transmission airline (slabline) connecting both ports, a mobile carriage movable parallel to the slabline, said carriage comprising a resonant coaxial probe sliding perpendicularly on the slabline;
- the center conductor of said resonant probe is an open-ended stab capacitively coupled to the central conductor of the slabline;
- said tuner comprises means for horizontal movement of said carriage and vertical movement of said open-ended stab inside said resonant probe.
An electro-mechanical tuner, comprising a slotted airline, a test port and an idle port is divided in to three sections, each section comprising a mobile carriage, which comprises a resonant probe, inside of which there is a central open-ended stub, which is capacitively coupled with the central conductor of said airline, said tuner is calibrated by measuring scattering parameters (S-parameters) between the test and idle ports at a given frequency (fo) and its two harmonics (2fo and 3fo), as a function of the horizontal and vertical position of each resonant probe, using a calibrated vector network analyzer (VNA), and saved in a calibration data file;
- said calibration includes five steps, step 1 consisting of measuring S-parameters of the tuner as a function of the position of probe 1, probes 2 and 3 being initialized, step 2 consisting of measuring S-parameters of the tuner as a function of the position of probe 2, probes 1 and 3 being initialized, step 3 consisting of measuring S-parameters of the tuner as a function of the position of probe 3, probes 1 and 2 being initialized, step 4 consisting of cascading the S-parameters measured in steps 2 and 3 with the inverse S-parameters of the tuner, measured when all probes are initialized, and step 5 consisting of saving the S-parameters collected and calculated in steps 1 to 4 in a total of 9 calibration data files, one for each of 3 probes and each of 3 harmonic frequencies.
Dependencies are inferred from the claim text.