diferencial configuration for 40Gbps

hello people
i'm doing a project at university of Aveiro. i'm looking for a configuration of a diferencial amplifier for 40Gbps application. i have already tested the cascode configuration, but i have a peak at 40GHz of 4 db ( i think it's because of bond wire (0.3nH)). existe some tecniques to reduce this peak?, the cherry-hopper confiduration is suitable?

PS: i'm using the D01PH tech.

thank you for your attention

The bond wire could be the cause, but 0.3nH is very small so I'm guessing it maybe something else. The peak may also be coming from the inductance effect of the emitter followers/source followers in you design (if you have any). If you do have an emitter follower/source follower running at a high current density, this will cause an inductive effect.

One way of getting rid of the peak is to use a cml/mcml type of design. By coming off the collector/drain, which is high impedance, will negate the inductive effect caused by an emitter/source follwer.

Be aware that the peak you are getting may also be helping you extend the upper 3dB bandwidth of your amplifier. Therefore, if you eliminate the peaking, you may also reduce the bandwidth of your differential amplifier.