RF layout in ADS
I want to draw a preamplifier layot in ADS. i want to know the special rules for RF layout design in(20MHz up to 2 GHz). in this frequency range the GNDvias are needed or not and if yes where should i insert them?
and in ADS how i can change an orbitaray metal shape to a trace or path?
you can use the Momentum of the ADS ,If you know the EDA of Boardstation of metor,It'll easy to layout and simulate. they are the best partener in MW and RF .
maryam.ha81
the GNDvias in RF are very important. Consider that a via can be consider as an inductor in the RF frequency range, so you need to insert a lot of vias in order to reduce the inductor and the resistor serie value. It is better to put some vias nearly possible to the GND pins of the device.
By
At high frequency, you had better put a reference plate (ground) beneath the trace (the so call "microstrip"). The width of the trace (transmission line) should be calculated carefully for matching (typically 50 ohm).
The grounding is very important at RF bands, bad grounding may cause severe parasitic effect, and even make the amplifier unstable. The grounding pin of the amplifier (usually is the source or emitter) should be grounding very well.
Sometimes, the both sides of the transmission line are also grounded by many vias. These vias are for EMI/EMC purpose. The typical rule is the interval of the vias should be less than 1/20 wave length.
thanks for your answers but i also need to know that if the back side ground plane in all cases is necessary or not. because of my special application, i need to use the other side for placing the elements and microstrip lines so i can't definea back-Ground plane.Is this a usual case in the RF/Mw boards or not and if yes in this case what is the optimum shape of the back-ground plane?
Why don't you draw the PCB layout in Powerpcb or Protel, and import it to momentum by gerber view?