RF Design Tips, Tricks & Tutorials

ADS Users’ RF & Microwave Designs & Applications

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Millimeter-wave SiGe IC Design Technology Overview

July 2nd, 2014 · Uncategorized

Liam Devlin of Plextek RFI presents a technology overview of mm-wave SiGe IC design using ADS in the June issue of Semiconductor today http://viewer.zmags.com/publication/6231d0ac#/6231d0ac/125

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Broadband (2-18GHz) GaN PA MMIC Design from Plextek

September 12th, 2013 · Uncategorized

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ADS Quick-Start Tutiorials and Free Online Training

September 3rd, 2013 · Uncategorized

ADS Training

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Simulate Envelope Tracking with Measured X-Parameter Model of a Power Amplifier

July 15th, 2013 · Uncategorized

Suppose you have a power amplifier (a real, physical amplifier) but not a model for it (a simulate-able schematic, for example) and you want to run envelope tracking simulations.  If you measure the amplifier’s X-parameters (including a drain or collector bias sweep), you can use the X-parameters as a model for simulating envelope tracking. This Application Note White Paper (20130715_Envelope_Tracking_Using_Meas_X_params) explains how.  There is also an example on the Agilent EEsof Knowledge Center that shows how to carry out these simulations. A login is required. You can register for the Knowledge Center by visiting https://edasupportweb.soco.agilent.com/portal/page?_pageid=36,472848&_dad=portal&_schema=PORTAL.

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ACPR and EVM contours from 1-tone load pull simulations

July 9th, 2013 · Uncategorized

Do you need to run a load pull on a power amplifier or device, and plot contours of adjacent channel power ratio (ACPR) and error-vector magnitude (EVM)? Do you need to plot the contours at specific modulated input signal powers, at specific output power levels, or at specific levels of gain compression?  How do you do this?

The technique described in a new ADS example generates contours from a one-tone, swept-power harmonic balance load pull simulation.  It is much faster than running an envelope simulation, and by means of interpolation avoids having to do an optimization to get data at a specific output power or at a specific level of gain compression.

Download the new ADS example and Application Note White Paper (20130628_ACPR_Contours_from_1Tone_Load_Pull) here (http://edocs.soco.agilent.com/pages/viewpage.action?pageId=213462866) an Agilent EEsof EDA Knowledge Center login is required.

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ADS Envelope Tracking Simulation Examples Updated

July 9th, 2013 · Uncategorized

Prior to running envelope tracking simulations, it is necessary to generate a shaping table from a harmonic balance simulation.  Shaping tables attempt to force the power amplifier to maintain constant gain or constant gain compression while their bias is being modulated.  This shaping table has to be written into a file prior to running ET simulations.

The ADS envelope tracking examples have been updated so it is now a very easy process to adjust the shaping table and write the data into a file automatically.  This makes ET simulations much easier to run in ADS, and enables designers to more easily experiment with different shaping tables.

One of the examples now shows how to generate a shaping table by maximizing the power-added efficiency at each drain bias value. A goal to maintain the gain to be constant or above some minimum value may also be added. The same example also has an alternative method of simulating envelope tracking in which a drain bias modulation waveform is generated from the data display.

The ADS ET examples and the White Paper Application Notes that describe them are on the Agilent EEsof KC: http://edocs.soco.agilent.com/display/eesofkcads/Applying+Envelope+Tracking+to+Improve+Efficiency

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ADS Tutorials, Videos and free Training to get started quickly!

June 17th, 2013 · Uncategorized

Looking for some great free training materials to get up and running on ADS quickly? The Agilent EEsof Knowledge Center had a lot of great course materials including videos for new users as well as users upgrading from ADS 2009 to ADS 2011 and ADS 2012!

If you aren’t yet registered for the Knowledge Center, its easy to sign up; just visit the Registration Page. In addition to training materials, there’s hundreds of great application examples that aren’t available in the ADS installation.

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Contours of Constant EVM from a Load Pull Simulation

March 13th, 2013 · Uncategorized

A primary task in amplifier design is determining the best load impedance(s) to present to a device.  Load pull is frequently used for this task, and ADS has many load pull simulation setups and data displays.   This new example shows how to plot contours of constant EVM from a load pull simulation.  

EVM is one method of measuring distortion, and this example enables you to clearly see trade-offs between EVM and output power, and take PAE into consideration also, when choosing the optimal load to present to a device.

This example is explained in a white paper and application note, Running a Load Pull Simulation and Plotting Error Vector Magnitude Contours, by Andy Howard.

You can also download the ADS example from the Agilent EEsof Knowledge Center: http://edocs.soco.agilent.com/display/eesofkcads/Contours+of+EVM+from+a+Load+Pull+Simulation

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References for Power Amplifier (PA) Design

February 25th, 2013 · Uncategorized

ADS Reference Material and Webpages (no login required):

ADS Reference Material and Webpages in the Agilent EEsof EDA Knowledge Center (login required):

A Typical Design Flow in ADS for Power Amplifiers:

ADS 2012 examples specific to PA Design.  Please note that you can browse to the example path shown for each below, and you can click on the hyperlink to see an online overview if you have a Knowledge Center login (since the online documentation resides within this web location).

ADS examples on the Agilent EEsof Knowledge Center (login required) related to power amplifier design

There are more than 80 examples or notes related to power amplifier design.  Do a search for “Power amplifier”.

This page has examples that show envelope tracking simulation: http://edocs.soco.agilent.com/display/eesofkcads/Applying+Envelope+Tracking+to+Improve+Efficiency

This page has an example that shows how to analyze Doherty power amplifiers: http://edocs.soco.agilent.com/display/eesofkcads/Using+ADS+to+Investigate+the+Performance+of+a+Doherty+Power+Amplifier

This is a fairly basic example of a power amplifier using a high-power device: http://edocs.soco.agilent.com/display/eesofkcads/power+amplifier+design+using+Freescale+device

 

This has a good collection of references on amplifier design:

http://edocs.soco.agilent.com/display/eesofkcads/ADS+2012+good+references+to+start+amplifier+design

App Notes and Webcasts (both upcoming and on-demand) about PA Design using ADS (archives include streaming video and slides to download):

Some classic references from Past Workshops & Seminars:

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New Envelope Tracking Examples and more!

February 22nd, 2013 · Uncategorized

ADS applications developer, Andy Howard, has created a new high-power amplifier Envelope Tracking (ET) example that includes a comparison of an X-parameter model and the original transistor-level amplifier with a 64-QAM signal.  With the 64-QAM signal it is easy to change the signal bandwidth and see the impact on the amplifier’s performance with Envelope Tracking:  20130208_Envelope_Tracking_Sim_Ex_3

Also, two existing ADS Envelope Tracking examples have been updated.  

  • The first example, 20130205_Envelope_Tracking_Sim, explains some of the basics of ET and how the bias modulator is implemented using behavioral models.
  • The second example, 20130205_Envelope_Tracking_Sim_Ex_2, shows how to model non-idealities in the bias modulator and includes many more simulation setups and calculations.   

In both of these two examples, many of the data displays have also been updated, making it much easier to make direct comparisons between two different ET simulations. And, they have a corrected method of determining the available source power, which enables the design to better maintain constant gain during envelope tracking. 

To download the full ADS workspace examples, click here and you’ll be taken to the Agilent EEsof EDA Knowledge Center

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