Guidelines and tips for LNA testing

I m doing a 12GHz LNA using ATF36077 phemt (avago). I hav fabricated and soldered the circuit.
My Vgs=-0.21V and Vdd=4.8V(operating point Id=10mA,Vdc=1.5V and Pin(max)=10dBm.

1)Can anyone explain the do's and dont's when testing the amplifier.

2)If the LNA is not working, what are the usual causes for this?

thanks

frist of all u need to know ur test setup
1) VNA "vector network analyzer" this is enough for most of the linear tests
2) u need a noise source , and noise figure measuring option
3) singal genrator , and spectrum analyzer to measure the 1 dB compression point

or what are the equipment u have ?

be carefull coz of the ESD sensitive device , also be carelfull when adjusting the bias point

u need to calibrate ur VNA

Khouly

My university lab doesnt have VNA.We only hav Network analyser,signal generator and spectrum analyser.
1)How am i to analyse the noise figure?

2)How to counter the effects of ESD when testing?

3)can u pls tell me more about adjusting the bias point?(should i apply the bias voltage -0.2 first before the vdd or the other way around? should i increase the vdd slowly from 0V to 4.8V or present 4.8V the moment i connect power supply?)

1) the network analyzer is VNA
2)check ur equipment datasheet and check if it is cable of noise figure measurments

3) the ESD . put the ground pad to ur hand when u dealing with the circuit

4) about the bias point u need to apply them both or the gate frist , then the drain

sometimes when the gate is float and u connect the drain the transistor will n't work again

khouly

thank u very much for the reply.

I dont understand what u mean by 'when the gate is float and u connect the transistor will not work again'. can u pls explain?

i mean sometimes wiith phmets , when u apply a supply to drain and make the gate is floating , the transistor will be burned out , and wont work again

khouly

hi Murlix could pls upload ur design here

check this application notes of anritsu about using thier VNA
http://www.us.anritsu.com/products/A...cat3=23&cat4=0

khouly

Hi abdoeng

i hav attached my ads .zap file for ur viewing.I am using ADS2005A.
My fabricated design is schematic 12GHzR3010_7.dsn and 12GHzR3010_8.dsn
both design are similar but the difference is the lumped component artwork used and the simulation performance.

I am still new to LNA design but i hope this useful for u.

hi murlix,thanks for ur response,i also design one with wide bandwidth from 8 up to 12 ghz with atf36077 with substrate epsr=6.15
thanks

hi abdoeng,
can u upload your design also or u could send it to my email(murlix16@gmail.com).
thanks

hi murlix,here my presentation of wide band amplifier,hopping help u

Hi ,all, can anyone upload a ADS project of a lna at 1.9 G or 2.1 G? also I have a question to ask, I have seen a schematic of a LNA in RF front end for basestation, it have phase shifters after the amp circuit and before the power divider, Why? Is it used to balance the phase between high gain mode and low gain mode?