Since resonance components were observed in the power plane relative to the excitation power source, the result was judged as Resonance NG (Not Good)<\/span>.<\/p>\n Since no resonance components were observed in the power plane relative to the excitation power source, the result was judged as Resonance OK<\/span>.<\/p>\n <\/p>\n After adding four capacitors in the simulation, the resonance components in the power plane fell below the allowable voltage limit, resulting in a Resonance OK<\/span> judgment.<\/p>\n <\/p>\n <\/p>\n The frequency characteristics graph of plane resonance analysis visualizes the maximum voltage of the target plane at each frequency.<\/p>\n Noise (electromagnetic waves) propagating between the power-ground planes of a printed circuit board undergoes multiple reflections at the plane edges. When the distance between the plane edges corresponds to half the wavelength (or its multiples) at a specific frequency, standing waves form. When plane resonance is present, the characteristic graph appears as the red line in Figure 2, showing voltage peaks at specific frequencies. On the other hand, when there is no plane resonance, the characteristic graph follows the blue line, indicating an increase in impedance as the frequency increases.<\/p>\n The far-field radiated electric field is analyzed using the 3-meter method.<\/p>\n
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\u25c9 Implementing Countermeasures for Resonance NG Areas<\/strong><\/span><\/h2>\n
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—— About DEMITASNX Resonance Analysis ——<\/h2>\n
\u3010Analysis Result Judgment Criteria\u3011<\/h3>\n
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\u3010Plane Resonance and Resonance Analysis with DEMITASNX\u3011<\/h3>\n
\nThis phenomenon is called **plane resonance**, and the specific frequencies where these occur are referred to as **resonance (peak) frequencies**.
\nThe power-ground plane is modeled as an **RLCG equivalent circuit**, and circuit analysis is performed using **SPICE simulations**.
\nThe analysis results are displayed as voltage distribution maps and frequency characteristic graphs.<\/p>\n<\/div>\n
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Relationship Between Allowable Maximum Voltage and No Resonance<\/h3>\n
\nAnalyzing the radiated electric field under the same resonance analysis conditions produces the result shown in Figure 3, where the red line indicates a higher radiated electric field.<\/p>\n<\/p>\n
What is Radiated Electric Field?<\/h3>\n
\nThe electric field strength (dBuV\/m) radiated from the PCB\u2019s power and ground planes at a distance of 3 meters is calculated.<\/p>\n<\/div>\n