Meters and Probes Evaluate EM Fields

Electromagnetic (EM) fields exist throughout many homes, institutions, and workplaces and can be life-changing depending upon their intensity. Fortunately, they can be detected and measured with portable EM field meters like the Wavecontrol SMP3. Depending upon the field probe attached, the SMP3 can make frequency-selective or broadband measurements of electric (E) field, magnetic (H) field and EM fields as high as 90 GHz in frequency. Probes are also available for H-field measurements from DC to 1 GHz and combination E/H-field measurements from 1 Hz to 10 MHz. With a suitable probe, the SMP3 EM field meter is a valuable measurement assistant for a wide range of applications, including for aeronautical, automotive, communications, defense, industrial, and medical testing. The SMP3 automatically detects the operating range of each “plug-and-play” probe and adjusts its operating controls and limits accordingly.

The SMP3 EM field meter is a multifunction unit, capable of broadband EM field measurements, static field measurements, and even low-frequency Fast Fourier Transform (FFT) spectrum analysis from 1 Hz to 10 MHz. Its wide frequency range, teamed with a suitable field probe, provides the measurement capability required for evaluating many emerging applications at millimeter-wave frequencies, including the second frequency range (FR2) of Fifth Generation (5G) wireless cellular networks. With a broadband model WPF60 probe, the SMP3 covers wide dynamic ranges for electric-fields (E-fields) from 1 MHz to 60 GHz: 1 to 1000 V/m for continuous-wave (CW) measurements and 1 to 55 V/m for root-mean-square (RMS) readings.

The SMP3 packs a great deal of measurement capability within a package measuring just 100 × 215 × 40 mm and weighing 635 g. It provides multiple tests, performing static EM field measurements, broadband field measurements (depending upon choice of probe) from DC to 60 GHz, and can function as a low-frequency (to 10 MHz) FFT spectrum analyzer. A substantial portion of the field meter’s package is devoted to a 480 × 272 pixel color thin-film-transistor (TFT) display to ease checking on measured values. When many in-field measurements are required, the EM field meter has enough built-in memory to record more than 1 million samples or registers and features a USB-C port for connection to a personal computer (PC) for analyzing captured test results.

Despite the small size, the SMP3 is highly automated, with built-in test functions to make measurements according to the weighted peak method (WPM) when comparing against industry limits (reference levels) or for workplace safety testing to comply with such low-frequency EM exposure standards as ICNIRP 2010, Directive 2013/35/EU, and IEEE C95-1. It automatically detects and adjusts for each connected probe. The SMP3 measures an EM field’s total strength as well as the energy readings in three axes (x, y, and z) and displays results in peak and RMS values, showing minimum, maximum, and average field-strength values. Among its automated functions, the SMP3 includes an automatic gain function to alert users of peak values when in rapidly changing EM environments, such as along manufacturing assembly lines. The meter includes a 2.4-kHz audible alarm signal to alert users of various operating conditions and when exceeding a set limit.

Each SMP3 EM field meter is supplied with useful accessories, including the firm’s “SMP3 Reader” PC software, a carrying case, USB cable, and an AC/DC charger for the SMP3’s internal lithium-ion (Li-ion) rechargeable battery. Options include internal GPS capability, probe extension cable (2 or 5 m), fiber-optic interface (10, 20, or 45 m), and a DC charger that connects to a motor vehicle.

Comparing EM Fields

How does the Wavecontrol SMP3 compare with existing EM field meters and probes? Take a look at the Narda NBM-550 EM field meter with its own set of field probes for measuring E, H, and EM fields. This unit covers a total frequency range of 1 Hz to 90 GHz when matched with the suitable field probe, also automatically detecting the connected probe, and setting levels within the meter for the most accurate measurements for the probe’s operating range. With an available probe, the Narda NBM-550 can perform WPM spectral measurements from 1 Hz to 400 kHz and WPM measurements according to IEC 61786-2 requirements.

Although it features a voice recorder for operators seeking to make notes during measurements, and a plug-in GPS receiver as an accessory, the Narda NBM-550 EM field meter offers less built-in data storage than the SMP3 EM field meter, with memory for about 5000 measurements. Still, both EM field meters have been described as “5G Ready,” meaning they have frequency coverage to detect and record EM emissions from 5G equipment and systems even as 5G networks increase their use of millimeter-wave signals above 30 GHz. To learn more about either EM field meter and its associated probes, please visit the Axiom website or contact us for guidance at (760) 806-6600.