Circuit board mounted, shunt capacitive filters are less effective at high frequencies because of the mutual inductance (M) that exists between the input and output ports. An approximate expression for the mutual inductance is M=(μh/2π)ln(h/a); where h=via length and a=radius of the via connecting the capacitor to the return plane. The reduced mutual inductance associated with the new, three-terminal, surface-mounted capacitor results in more than 15 dB increased attenuation compared to two-terminal capacitors over the 0.3-6.0 GHz range with 50 Ω source and load terminations
C. N. Olsen et al., "Improving the High-Frequency Attenuation of Shunt Capacitor, Low-Pass Filters," Proceedings of the IEEE International Symposium on Electromagnetic Compatibility (2001, Montreal, Quebec), vol. 1, pp. 487-489, Institute of Electrical and Electronics Engineers (IEEE), Aug 2001.
The definitive version is available at http://dx.doi.org/10.1109/ISEMC.2001.950689
IEEE International Symposium on Electromagnetic Compatibility (2001: Aug. 13-17, Montreal, Quebec)
Electrical and Computer Engineering
Electromagnetic Compatibility (EMC) Laboratory
Keywords and Phrases
0.3 to 6.0 GHz; 50 Ohm; Capacitors; Equivalent Circuits; High-Frequency Attenuation Improvement; Inductance; Input Ports; Load Terminations; Low-Pass Filters; Mutual Inductance; Output Ports; Shunt Capacitor Low-Pass Filters; Source Terminations; Surface Mount Technology; Three-Terminal Surface-Mounted Capacitor; Electric Impedance; Electric Load Management; Schematic Diagrams; Shunt Capacitors; Electromagnetic Wave Attenuation
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Article - Conference proceedings
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