Image Rejection Filter Suggestions

[SeriousTyro]

Hi,

I'm building a Wifi 2.4GHz receiver for class using a 0.13 um process operating at 1.2V.

I need some advice. I'm making a heterodyne receiver and somewhat finished my LNA design.
The next part after the LNA would be the Image Rejection Filter for the mixer and one of the
specifications is to have IRR=40dB. From what I read, the Hartley and Weaver architectures
typically have a range of 30-35dB.

Does anyone have suggestions on some architectures or any good papers for an image refection filter?

Thanks,
Tyro

 

[vfone]

To design this image filter, very important is the frequency spacing between RF and LO signal, which is the IF frequency.
If the IF frequency is very low compared to RF frequency, would be a challenge to design an image reject filter with 40dB rejection.

 

[tony_lth]

Image reject can be implemented by IF1 & IF2 with an external hybrid.
Also, biasing the IF1 & IF2 maybe help.

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Image reject can be implemented by IF1 & IF2 with an external hybrid.
Also, biasing the IF1 & IF2 maybe help.