Wat maakt RF/magnetron-PCB's speciaal dan andere conventionele printplaten?

Bij het werken met hoogfrequente signalen ontwerpen, de plaatsing en routering van PCB-sporen zijn van groter belang dan DV- of laagfrequente circuits.

Wanneer sporen parallel aan elkaar worden gelegd (either adjacent or on opposite sides/different layers of the board) they form a very tiny capacitor.

When traces are routed around components they can form very tiny inductors.

Nu, as anyone who knows about AC circuits will attest, two things are unavoidable:

1. Capacitive reactance is inversely proportional to frequency.
2. Inductive reactance is directly proportional to frequency.

Both of the above are measured in Ohms (as they are a measure of a circuit’s resistance to current flow).

Dus, those tiny capacitors created by the parallel traces will cause leakage. Bovendien, the interference and the inductors created by wiggling traces around components will introduce a non-linear resistance into the circuit (and could even act as an antenna, producing undesirable interference elsewhere).

These issues are sometimes used for constructive purposes to reduce noise but make HF circuit design more of a challenge.

Bijvoorbeeld, you might see traces that are deliberately “wiggly”.

Lees verder: 16 Stappen op magnetron PCB-ontwerp

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