Choosing Blocking Capacitors – It’s More than Just Values

This article explores improving RF performance, but with less capacitors that, in their ideal form, block DC current and pass AC current. This makes capacitors a fundamental building block in Radio Frequency (RF) and microwave systems. They are often used to create filters, generate DC protection, and to create bypass networks. Often designers use rules of thumb or approximate equations to link capacitor values to final RF performance. As system requirements constantly require higher performance these assumptions are no longer valid. Knowles Precision Devices DLI facility has looked in detail at real world performance that can’t be predicted by design theory, and then took measurements with common capacitor bypass networks to support our analysis.