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60 GHz Mixed Signal Active Load-Pull System for mm-wave Devices Characterization. Delft Institute of Microsystems and Nanoelectronics. IQ Mixer. From RF source. Attenuator. IQ Mixer. IF Mixer. PA & HPA. To IQ Mixer. To IQ Mixer. Attenuator. x3 Multiplier. PA. Magic T.
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60 GHz Mixed Signal Active Load-Pull System for mm-wave Devices Characterization Delft Institute of Microsystems and Nanoelectronics IQ Mixer From RF source Attenuator IQ Mixer IF Mixer PA & HPA To IQ Mixer To IQ Mixer Attenuator x3 Multiplier PA Magic T Bi-directional WG coupler Bi-directional WG coupler Luca Galatro, Mauro Marchetti, Marco Spirito Summary—This work presents an active load-pull system for mm-wave frequencies (i.e., 50-65 GHz) based on the mixed-signal concept and implemented entirely using low-loss wideband waveguide. The proposed system addresses the emerging needs for accurate large signal measurements for model validation and development and in-band (i.e., EVM) and out-of-band linearity characterization of MMIC PAs developed in the 50 to 65 GHz range. 1. Active Mixed Signal Load-Pull 3. The Waveguide Architecture • Mixed-signal load –pull approach based on IQ signal up-conversion • Advantages • No phase variation of the synthesized reflection coefficient • Realistic communication signal detection using broadband DAC and ADC Waveguide components enable strong reduction of losses in the signal path in respect to coaxial cables. RF signal splitted using a WG Magic Tee , providing low insertion loss and high isolation between the two output branches. 2. System Configurations IQ mixer for signal up-conversion, attenuator required to optimize matching with following PA. Bi-directionalWG coupler allowing high directivity signal detection. HPA in the output section for optimized signal injection level. Down-conversion using x3 multiplier on mixer LO port to reduce cost and simplify LO distribution chain. • Load Pull: Large signal characterization of mm-wave devices for compact model development and validation • Modulated Signal Characterization: Characterization of signal quality (EVM) under broadband modulated excitation. 4. Preliminary results Basic system functionalities have been tested on a hybrid coaxial-waveguide prototype. Here a load-pull measurement performed on a Millitech AMP 15-02100 amplifier at 60 GHz for 41 load conditions on a reduced input power sweep is shown, along with a 250 MHz bandwidth QPSK signal upconverted to 60 GHz by using the WG IQ mixers