How does a class B amplifier reduces even order harmonics

Hi

Actually it does not, the second harmonic is very much present in class B.

However it is way easier if you read this in the exellent book by Cripps:
"RF Power Amplifier for Wireless Communication" section 3

I think you can find the book in Ebook section.

Regards

Could it be that you mean symmetrical class B (or push-pull) amplifier?

yes really I meant class B pushpull amplifier

Well, then the answer is very simple and general: Assume that the output waveform of the amplifier has a considerable degree of distortion, but is exactly symmetric, it will have no even harmonics at all. This can be seen from fourier series respectively fourier transformation. See the fourier series of a square or trapezoid waveform as an example.

Push-pull Class B

Hi vfone,I dont understand why ID2 is negative (-ID2)?and why ID=ID1-ID2? Thank you!

It is purly because of the hybrid coupler