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What is load pull?

Load pull enables RF designers to characterize their high power devices in non-50ohm conditions. A common misconception is that a Vector Network Analyzer (VNA) can provide similar results. VNAs allow users to measure devices in a 50ohm environment at low powers, also known as small signal s-parameters, but they do not provide the full picture. A load pull system actually tunes to specific impedances and reports measurement parameters in a real-life condition. Gain compression of an active device
  Gain compression of an active device

When an active RF device is driven into compression non-linear artifacts appear. Gain compression is one of the first parameters designers will look at when optimizing their devices. The compression point determines how deeply the device is driven into its nonlinear state. When a device reaches its compression point the gain of the devices drops, meaning that the output of a nonlinear system is not directly proportional to the input.


Why is load pull important?

Load pull allows the user to measure and sweep multiple parameters. The most common parameters designers focus on when optimizing their devices are: gain, output power, voltage current, power added efficiency, intermodulation (IMD,TOI), error vector magnitude (EVM) etc… By sweeping the smith chart we obtain load pull contours, as shown in the image below.

Find out more on Active and Hybrid Load Pull.


Single parameter contour Multiple parameters contours Single parameter contour   Multiple parameters contours


Focus Microwaves

Focus Microwave has pioneered the development of tuner technology for Load Pull, Harmonic Load Pull and Noise Measurements. The company’s products cover the widest frequency range with fundamental tuners available from 10MHz up to 65GHz. This allows you to cover multiple standards with one tuner. For Harmonic Load Pull, the Focus MPT tuner allows you to easily calibrate and tune harmonics. Focus Microwaves automated, multi-harmonic and manual tuners, test fixtures and calibration kits are available for purchase or rental from Electro Rent. Automated tuners from Focus Microwaves are used in applications including Load Pull, Pulsed IV and Noise Measurements.

Electro Rent Europe is a world partner for Focus Microwaves tuners, software, fixtures and accessories.


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Tel HQ EMEA: +32 15 740 800
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Related links:
High speeds Hybrid Load pull is the main new feature


AU4850 Pulsed IV/RF Characterization System
Auriga Multiple-Band High-Power Bias Tees
Auriga PHD3100 Pulser Head Series
Cardiff Model Lite
Harmonic Load Pull
Integrated Pulsed I-V