Problem with HB simulation of a FET mixer

[khouly]

i am doing a reciver mixer right now ,
the RF =7.3 Ghz the LO= 5 GHz , the IF = 2.3

the prblem is while the HB simulation , i have found that the 2 harmonic of the LO 10 GHz is mixing with the RF 7.3 and produce a signal at 2.7 GHz , which is comparable in power with the desired singal ,

i am using a single trnasistor FET mixer , is there any solution to reduce the interference ,

or i need to space the LO to 6 GHz , i foud the interferer is away

what do u think ?

khouly

 

[flatulent]

Re: Mixer problem

Your best bet is to avoid mixing products near the IF rather than making them smaller.

You should spend a few hours making a spread sheet to predict mixing products and then do a "what if" analysis where you cut and try several IF frequencies as well as high side and low side LO frequencies.

 

[khouly]

Mixer problem

thanks Flatulent

yeah , i retured back to the system analysis again , and i am chinking the IF , i found that 6 GHz for the LO will give good results

the problem is the transistor is wide band , so the 2LO multiplication occur easily

i will try to make a detailed IF analysis and then check

khouly