Microwave measurements and test equipment

Updated March 10, 2007

Welcome to the Microwaves101 virtual laboratory! Here you can review the fundamentals of microwave testing, learn about some commonly used microwave test equipment and setups, and discover some troubleshooting techniques gleaned from years of laboratory experience. Study hard and soon you will be able to call yourself a lab rat! We use this page as the index for all microwave measurement subsections.

Here's links to our growing list of test equipment and measurement pages:

Load pull measurement of power devices (sponsored by Auriga Test Systems!)

Noise parameter extraction using source pull

Distortion measurements (sponsored by Matrix Test Equipment, Inc.!)

RF probing (new for September 2006!)

Slotted-line measurements

Impedance tuners

Frequency meters (a.k.a. wavemeters)

Spectrum analyzer measurements
including third order intercept, AM and FM, pulsed RF parameters, and EMI

Power meter measurements
including one-dB compression

Network analyzer measurements

Oscilloscope measurements
including recovery time, and rise/fall time

Group delay measurements
including time domain and frequency domain techniques

Curve tracer measurements:
MESFET example
Voltage regulator example
Schottky diode example
A useful modification to the 370B curve tracer
How to control oscillations

Historic test equipment
some cool photos!

Measuring dielectric constant (awaiting inputs!)

If you spend any time at all in a microwave lab, please review our discussion of connector care now!

Fundamentals of microwave testing

A couple of notes about Agilent before we begin discussing TE (test equipment)... first, Agilent is the 800 pound gorilla of microwave test equipment. What microwave engineer wouldn't want a new 110 GHz analyzer under his/her Christmas tree? And second, for those of you who just arrived from another planet, Agilent used to be Hewlett Packard. Hewlett Packard built all of the antique test equipment that lines the shelves of your test equipment crib. Guess why it's all there? The equipment was built to last forever. Some of it will still be there when you retire. They also standardized the instrument controller interface bus (HP-IB) so that pieces of gear could talk to one another. Please see our Microwave Hall of Fame to learn more about Microwave Superheros Bill Hewlett and Dave Packard and the company they started in a garage.

There are many forms of microwave measurements, and here we will break them down into a few broad categories. Perhaps your company would like to contribute to and/or sponsor a page on one of these topics!

• Transmission and reflection parameters (small-signal)
• Large-signal parameters (gain compression, load-pull, etc)
• Frequency generation and conversion
• Waveform analysis (time and frequency domains)
• Noise figure and noise parameters
• Signal purity
• Antenna patterns

Some of the TE tools of the microwave trade include:

• sweep oscillators and synthesizers
• network analyzers (vector and scalar)
• frequency counters and meters
• noise figure meters and test sets
• power meters
• spectrum analyzers
• high-speed digitizing oscilloscopes
• detectors
• curve tracers
• impedance tuners
• RF and DC probes

Some commonly-used test setups that will be described by Microwaves101(when we get around to it for crying out loud!) are:

• Network analyzers (scalar and vector)
• Large-signal test bench for P1db
• TOI measurements
• Noise figure test setups
• When to use waveguide
• Group delay measurements in time and frequency domains
• Switching time measurements
• Time domain measurements
• I-V measurements, static and pulsed
• Load pull and source-pull measurements

And we will share some troubleshooting tips with you:

How to know when your amplifier is oscillating, and what to do about it.

Common test figure problems: open circuit, short circuit, broken connectors.

Looking for a missing test equipment manual?

Manualsplus.com has what you need!

Want to rent some TE?

Technical Diagnostic Services, Inc. (www.test-equipment-rental.com) provides measurement, test, and diagnostic equipment covering the United States. They stock equipment from over 250 vendors for hundreds of applications. Equipment is available for short or long term rental, lease purchase, and sale. The also provide NIST traceable calibration services with quick turn-arounds, electrical systems training, and services.

Contact:
4300 Beltway Place, Ste. 120
Arlington, TX 76006
817-465-9494 1-800-225-7271
817-465-9573 Fax

Tell him to cough up some cash for this free ad!