Digital hybrid load pull system

A digital hybrid load pull tuner comprising:

• a digital, closed loop active signal injection tuner, and
• an electro-mechanical (passive) slide screw tuner, both said tuners using a common slotted airline (slabline) having a test port and an idle port and being divided into two sections, a first section towards the test port hosting part of the active injection tuner, and a second section towards the idle port hosting the passive slide screw tuner;
• wherein
• the digital, closed loop active signal injection tuner comprises:
• a digital electronic tuner including N switching elements (N>4) and having a test port and an idle port, and
• a circulator having three ports, port #1, port #2 and port #3, and two signal couplers incorporated in the slabline, a first adjustable signal coupler and a second signal coupler, each having an input, an output, a coupled and an isolated port, and a magnetic coupling loop inserted into the slabline, and an amplifier having an input and an output port;
• and wherein
• both signal couplers share the slabline,
• the first adjustable signal coupler is mounted on a first mobile carriage towards the test port of the slabline, and the second signal coupler is inserted between the first adjustable signal coupler and the slide screw tuner;
• and wherein
• the coupled port of the first signal coupler is connected to the port #1 of the circulator, the port #2 of the circulator is connected to the test port of the digital electronic tuner, the port #3 of the circulator is connected to the input port of the amplifier, and the output port of the amplifier is connected to the coupled port of the second signal coupler.