Focus created, in 2000, the Programmable Harmonic Tuner (PHT) using Harmonic Rejection Resonators and in 2004 the wideband multi-carriage harmonic tuner concept (MPT), for which it holds several patents.
The PHT tuners are now discontinued but always supported.
Harmonic Tuners - MPT
- Two, three (or four) wideband probes, cascaded and independently movable inside the same slabline and
- Appropriate calibration and tuning routines
These tuners allow, among other, generating independent impedances at two, three (or four) harmonic frequencies, simultaneously and accurately. Impedances at other than harmonic frequencies F1, F2, can also be tuned, as long as they satisfy the relation F2 > 1.2*F1.
The most popular tuner types are
- the MPT (or MPT-Classic) with three probes (up to 3 frequencies) and
- the MPT-Lite with two probes (up to 2 frequencies).
Tuning speed is around 2 seconds  and tuning accuracy 40 to over 50dB. The patented de-embedding calibration algorithm allows 3-probe MPT’s to be calibrated in less than 20 minutes per set of frequencies (Fo, 2Fo, 3Fo). The critical characteristic of “harmonic tuning isolation” is controlled by the MPT software and is, typically, better than 45dB. This restricts possible PAE measurement error, due to harmonic-to-fundamental tuning leakage, to less than ±1%.
MPT's are available from 400MHz to 67GHz in various multi-octave bandwidths :
The model number of each tuner is based on the frequency range and optional on the internal structure:
« xx » = Maximum frequency [GHz]
« yy » = Minimum frequency [0.1GHz]
« zz » = Number of probes, connector type, maximum power or other
MPT-xxyy (example: MPT 1808)
Fundamental (Fo) frequency coverage:
Fo ..... yy to xx [GHz] (example: 0.8GHz < Fo < 18 GHz)
Fo & 2Fo .... yy < Fo [GHz] < xx/2 (example: 0.8GHz < Fo < 9GHz; 1.6GHz < 2Fo < 18GHz)
Fo & 2Fo & 3Fo .... yy < Fo [GHz] < xx/3 (example: 0.8GHz < Fo < 6GHz; 1.6GHz <2Fo < 12GHz; 2.4GHz < 3Fo < 18GHz)
 MPT's require external computing power with >4GB RAM and 2GHz >dual-core processor.