The PCB world is in flux and an inrush of new designers is appearing on the horizon. Unfortunately, marketing material from manufacturers and CAD companies continues to spread outdated design guidelines that are easily misapplied, or they are simply wrong. One of these design rules that appears to be endemic is the critical length rule for transmission lines. This rule is used … [Read more...]
Placing a Metal Plate in Front of a EUT May Not Be Enough to Solve Radiated Emissions Exceedances or Radiated Susceptibility Failures
EXAMPLE OF AN EUT WHICH HAS FAILED RADIATED SUSCEPTIBILITY As described in reference 1, the EUT was exposed to a radiated immunity test at a level of 20V/m. The side which contained a vertical metal plate, with an approximately 0.3m x 0.3m dimension and which was electrically isolated from a metal baseplate failed at 12V/m and 300MHz. On the other sides of the EUT, … [Read more...]
A Short History Of A Few ITEM Issues
1977 My first issue of ITEM (Interference Technology Engineers Master) is from 1977. Was this the first issue of ITEM? No, it was not. However, it was my first issue. Why? I got my start in EMC in 1976 while working for the US Navy and was too late to get the 1976 issue. I graduated from college in 1975 and moved from Code 2330 (Nuclear Controls Engineering Division) at Mare … [Read more...]
Telecommunication Testing On Relevant RF Components
Introduction The telecom industry has undergone rapid development in the past several decades. Digital communications methods have advanced, requiring increased bandwidth and frequency coverage. This advancement has complicated an RF measurement system’s capability to accurately characterize system components. The 3rd Generation Partnership Project (3GPP) provides modern … [Read more...]
A Simple Guide to Antenna Selection
INTRODUCTION Selecting an antenna for testing can sometimes be straightforward but often requires some specific consideration. One aspect in antenna selection is knowing the intended test frequencies and then selecting a matching antenna. Not all antennas are created equal, and when it comes to frequency different antenna styles perform better at some frequencies and … [Read more...]
HOW TO PREPARE YOUR PRODUCT AND YOURSELF FOR EMC TESTING
INTRODUCTION Your product has EMC requirements. You have to test it to demonstrate compliance with those requirements. How do you prepare for the test? How do you prepare your product for the test? These are two different areas that need preparation before you go to the lab. Let’s look at them, one at a time. HOW DO YOU PREPARE FOR THE TEST? First, you need to … [Read more...]
The Internet of Things, Wireless and Security
Summary This article gives an overview of international and domestic efforts to protect our connected world. These efforts will be ongoing in perpetuity as the world becomes more complex, riskier, and increasingly exposed to many varieties of threats. Across the Pond The European Union (and the UK) are actively addressing the security of wireless devices, as outlined … [Read more...]
Things Not On the Schematic: How the Parasitic Element Affect Results
The engineer had found the use of a capacitor on a specific trace would solve a radiated emissions issue. However, placement on the connector where we put the capacitor during engineering work was not a production solution. So, the capacitor which was moved less than 1 inch away from the connector and turned sideways to fit on the circuit board. However, this degraded the … [Read more...]
EMC Design in Power Electronics Part 2: Noise Coupling Mechanisms
In the previous article of this series, we looked at some of the major noise considerations in different power regulator topologies. Noise from these sources eventually makes its way to other components, and it could interfere with other portions of a system. Depending on the types of components used elsewhere in the system, noise may be innocuous or it may cause a design to … [Read more...]
EMC Design in Power Electronics Part 1: Regulators
INTRODUCTION Modern electronics demand low EMI and EMC conformance, both of which are related to component selection and physical layout in the power supply section of a device. Many more designs are demanding higher power levels alongside high power efficiency, as well as low-noise power supplied to mixed-signal systems. As a result, EMI and EMC challenges are more apparent … [Read more...]
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