Optimize Doherty power amplifiers

Your task

You are responsible for developing a Doherty amplifier for a high-performance radio transmitter. Whether it is for 5G, SatCom or any other application demanding high performance and reproducibility, the challenges remain the same:

• How can you be sure that you are getting the maximum possible performance from the design?
• How can you evaluate its sensitivities and variations for series production?

T&M solution

With the R&S®SMW200A dual-path RF vector signal generator, which perfectly addresses the dual-path architecture of the Doherty, and the R&S®FSW signal and spectrum analyzer, you now have the toolkit you need to gain previously inaccessible insight into your design.

By performing a precise, repeatable and automated sweep of the amplifier inputs, you:

• Establish best-case performance of key parameters such as efficiency, linearity and power
• Make an informed choice regarding the best input architecture, especially for fixed RF input split
• Analyze the sensitivity of different design scenarios and understand how your design will perform in series production

Application

Running a test campaign while changing the drive signals in the two Doherty paths enables complete amplifier design characterization.

The R&S®SMW200A vector signal generator outputs two signals whose relative linear (amplitude and phase) or non-linear (e.g. shaped) characteristics are varied with precision.

The R&S®FSW signal and spectrum analyzer not only returns scalar quantities such as spectral regrowth and EVM, but also AM/AM and AM/PM, gain and peak envelope power (using the R&S®FSW-K18 option).

This rapidly acquired data provides you with previously invisible insights for a well performing signal split design for dual-path Doherty.

You are assured of the highest possible performance from any set of devices no matter which of the following you use:

• Fixed RF input splitter
• Programmable RF splitter
• Dispersive input splitter
• Dual-input digital Doherty