Taking a look at every kind of EMI antenna
Keywords:ETS-Lindgren? EMI? antenna? testing? hybrid?
Log-periodic antennas
Log-periodic antennas generally cover frequencies from 100MHz to 1GHz, although some start at 300MHz. A basic log-periodic antenna is polarized, meaning you may need to rotate it and run tests with the antenna mounted horizontally and then vertically relative to a ground plane. Some log-periodic antennas are dual-polarised, which lets you get measurements in both the horizontal and vertical planes at the same time. Many log-periodic antennas, especially the small ones, come in kits that let you carry them around and use them anywhere.
If you're on a particularly tight budget, you can use a DTV antenna for EMC troubleshooting (see bottom photo on this page). If you use a DTV antenna, remember that is has a 75? impedance so you need an adapter to convert it to 50?.
The ALC-100 is one of several log-periodic antennas from Com-Power. Covering 300MHz to 1GHz, the ALC-100 can handle 50W input power when used for radiated immunity testing.
The 3145BDP from ETS-Lindgren is a dual-polarised log-periodic EMI antenna with a stated frequency range of 100MHz to 1.1GHz.
Designed for FCC radiated emissions testing, the SAS-512-7 log-periodic antenna from A.H. Systems cover frequencies from 190MHz to 7GHz, a considerably wider bandwidth than other log-periodic antennas.
The LP60 log-periodic antenna from Sunol Sciences covers 1.3GHz to 6GHz. Other antennas in this series have low frequencies starting at 400MHz. The antenna can handle 10W input signals when used for radiated immunity.
Designed for high-power EMI immunity testing, the ATR200M6G from AR can handle up to 5kW input power. Its frequency range is 200MHz to 6GHz. The bent elements reduce width, letting it fit into some EMI chambers that would otherwise be too small for it.
The HyperLOG 7060 X antenna from Aaronia is an active log-periodic antenna with a frequency range of 700MHz to 6GHz. It's designed for precompliance emissions testing and troubleshooting and you can connect it directly to a spectrum analyser.
The LPDA-0801 from TDK RF Solutions covers 80MHz to 1GHz for emissions and immunity testing. For immunity, it can handle up to 2.5kW input power.
If you suddenly find that you need to troubleshoot EMI problems on a budget or on a weekend (or both), you can try using a consumer-grade DTV antenna. This log-periodic antenna from Terk lets you mount the elements in either a horizontal or vertical orientation.
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