Application Note #102: RF Power Costs Money, How Much Do You Really Need?
This application note outlines, describes and answers the question "RF Power Costs Money, How Much Do You Really Need?".
RF power amplifiers are probably the least understood and poorly treated assets in your laboratory. This article will explain in the basics of how to select your amplifier for a given test application. We will walk through the basic steps that determine the minimum RF output power required to reliably develop the field strength that your test requires. So you need to assemble an automated immunity test system that will allow you to support EN1000-4-3 and -6 with a limited budget. You can go to an antenna catalog and pick out an antenna that covers the right frequency range and the graph will tell you how much RF power you will need. Now you can call your local IFI amplifier representative for a quote for an amplifier that will give you just enough power. Pick up some coax cables and a software package and you are on your way. Actually IFI can help you with each of these items and provide technical guidance so you buy the right items in one package!
Now let’s consider a few more pieces of the puzzle. Try to answer these questions……
- Will that antenna fit in your test area at the correct distance from that gigantic rack of electronics that you call an EUT?
- Will the amplifier have enough headroom to overcome all of the system losses like coax cables, connectors and antenna VSWR, room wall coupling and still operate in the linear region across the band with 80% AM modulation?