Very low frequency tuner with adjustable dielectric
View Patent ↗A low RF frequency electro-mechanical load pull impedance tuner uses four rotary, remotely controlled variable shunt capacitors and four fixed series transmission lines to create up to 10 8 independently controllable impedance states at each frequency covering the entire Smith chart in the frequency range between below 1 and 5 MHz; the capacitors and control motors and gear are immersed in a mixture of dielectric fluids inside individual sealed containers including also adequate liquid stirring mechanisms. Appropriate, Error Function based optimization algorithms, allow fast impedance tuning at the fundamental frequency at the output of DUT's operated in high gain compression. Stepper motors, drivers and control software are used to remotely control the variable shunt capacitors of the tuner and allow it to be automated, pre-calibrated and used in an automated load pull measuring setup.
1. A very low frequency electro-mechanical impedance tuner comprises an input port followed by a first transmission line, an output port preceded by a second transmission line, and a cascade of at least four tuning modules inserted between the first and the second transmission lines and submerged in a continuously mixed emulsion of dielectric fluids with different dielectric permittivity ε r each;
wherein
each tuning module comprises a series transmission line connected to a shunt, remotely controlled variable rotary capacitor,
and wherein
the remotely controlled variable rotary capacitors are submerged in a container with an emulsion of dielectric fluids effectively mixed by means of an independent recirculating fluid pump.
2. The very low frequency electro-mechanical impedance tuner as in claim 1 ,
wherein
each variable rotary capacitor with its control is submerged in an individual container filled with the emulsion of dielectric fluids and includes the means for effectively mixing it;
and wherein
the variable rotary capacitors are connected with the associated transmission lines via sealed feedthrough plugs.
3. The very low frequency electro-mechanical impedance tuner, as in claim 2 ,
wherein
the containers is made of electrically non-conductive material.
4. The very low frequency electro-mechanical impedance tuner, as in claim 2 ,
wherein
the container is made of metal.
5. The very low frequency electro-mechanical impedance tuner, as in claim 1 ,
wherein
the means for effective mixing the emulsion of dielectric fluids comprise blades attached to an axis linked to the variable rotary capacitor.
6. The very low frequency electro-mechanical impedance tuner, as in claim 1 ,
wherein
the means for effective mixing the emulsion of dielectric fluids comprise at least one independently controlled liquid re-circulation pump.