need help in mixer design bu ADS

[varuniyengar]

wat abt LO power set it to -5dBm or some +dBm value remove var form the subcircuit can u post the HB engine setup

 

[gribi20]

its working with no mistakes but in result page what should I choose ?

 

[varuniyengar]

Name the output wire to the load as Vout and then simulate. After simulation open the result page place the graph and select Vout as output select the type of output ( spectrum in dB, dBm, Smith Chart ot time domain) and thats it. If you know the mixer performance equation we can do a lot more.

 

[gribi20]

I did it , and I got a result I have chosen different frequency based on the diode I selected , RF frequency was 1200 Mhz and LOfreq was 950 Mhz . I want to know how to calculate Conversion gain and loss ?

 

[varuniyengar]

please post the circuit with the harmonic balance engine setup

ConvGain=dbm(mix(Vout,{1,-1}))-RFpower
where 1 is the RF input
-1 is the LO input

---------- Post added at 19:35 ---------- Previous post was at 19:30 ----------

Use this equation to find the Conversion Gain
in the result window use the equation option and try to configure the equation and see the results.

 

[gribi20]

Those are the circuit and subcircuit

 

[gribi20]

in the result window I used this equation but there is something wrong did not work with me ConvGain=dbm(mix(Vout,{1,-1}))-RFpower.

 

[varuniyengar]

ConvGain=dBm(mix(Vout,{1,-1}))-RFpower should be used.

The difference is change dbm to dBm

 

[tony_lth]

1. It seems that your 1st transformer midpoint don't connect rightly. can you check it?
2. Why your RF and LO power unit is "_dBm"? Why not "dBm"?

 

[varuniyengar]

tony_lth
the connections and working is all fine. its _dBm because just the value is initialized and the converion is done in the RF or LO port thus mentioning dBm is unnecessary

 

[pancho_hideboo]

2. Why your RF and LO power unit is "_dBm"? Why not "dBm"?

In ADS Netlist, unit starting from "d" is not permissible.
And words starting from ";" and "_" mean comment.

So you have to write "_dBm" or ";dBm" instead of "dBm".

 

[gribi20]

Thanks for all of you ,
how do I use DC bias in this design ?
also , what are the steps of designing a balun in ADS and using Microstrip Scamatic

 

[varuniyengar]

Why DC bias ?
You can use the balun available in ADS palette or using ADS momentum design develop the hybrid or balun and then construct the subcircuit and use it.

 

[gribi20]

so , by constructing hybrid or balun can I have a DC bias in subcircuit ? are there some examples for constructing hybrid?

---------- Post added at 10:58 ---------- Previous post was at 10:18 ----------

I want to calculate Noise power and Spurious by doing this equation
NoisePowerTotal_dBm=10*log(sum(NoisePowerSpecDens*(0.1 MHz)))+30
there is something wrong with this equation ,may you check it out plz

 

[varuniyengar]

DC bias I am sorry! I am not the right person. But Noise power can be calculated directly using HB engine noise analysis.

---------- Post added at 21:30 ---------- Previous post was at 21:29 ----------

Will confirm the formula by Saturday.

 

[tony_lth]

NoisePowerTotal_dBm=10*log(sum(NoisePowerSpecDens* (0.1 MHz)))+30

It is not right. You can integrate the noise spectrum curve vs freq offset to get the noise power.

 

[gribi20]

lets say I wanna use RF frequency 20 GHz,How much would I choice RF power ?and what is the relationship or the equation?
Thx

 

[varuniyengar]

It depends on the power handling capability of the circuit developed and also more importantly your Balun or Hybrid.
Keep in mind whether ur circuit can handle 20 GHz? I think you need a very tight diode model to work at such high frequencies.

 

[jaish]

hey everybody..

Can anybody tell me about simulation of return losses in a mixer..

 

[varuniyengar]

hey everybody..

Can anybody tell me about simulation of return losses in a mixer..

Use S-Param engine in ADS