power amplifier input matching

[sinato]

how to match the input of power amplifier ??

 

[WimRFP]

Normally the active device supplier provides so called large signal input and output impedances. This can be in the form of Z = a+jb, or curves on a Smith Chart. You should provide the conjugate value (Z=a-jb) towards the active device.

These values are strictly spoken valid for a certain type of input and output matching network, output power and supply voltage. You may check an application note, or test schematic as used by the component manufacturer. The reason for this is that in class AB, B and C the input and output impedance depend on the termination as seen from the active device for harmonics also.

Actual matching can be done with lumped component (for example an L matching network), (micro)strip or combination of both. Manufactures of active devices sure have information on the actual procedure on their website. Suggested reading: Solid State Radio Engineering, Krauss, Bostian, Raab.

In case of wide-band matching, the matching is mostly done in steps to get the wide-band performance. This procedure is more elaborate as you have more variables (such as pass band ripple).