How much is the power capacity of Lange coupler?
the parameters are as follows:
width of the finger=190um
space between two fingers=27um
thickness of conductor(Cu)=35um
freq:1350MHz-1850MHz
Er=2.65
thickness of dieelectricity=0.41mm
thickness of conductor(Cu)=35um
s21=s31=-3db (Hybrid coupler)
would you please give me some advice in detail?
the space between the finger is 27 um,i am afraid it will breakdown when combining 20 Watts power in balanced amplifier
You need to consider maximum current through the traces. You can use a 2.5D EM simulator too look at current density (use Sonnet because Momentum current visulatization is flawed). You can also just use coupled line models in a HB simulator and measure the maximum current. Find skin depth so you can calculate cross section of trace that current flows through. Then find fusing current of conductor for that cross-section and make sure you are below it. The fusing current is for a wire in air so it is worst case. Heat dissipation on Alumina or Aluminum Nitride will be better.
Again use HB simulation so find maximum voltage between lines and be sure this is below breakdown of air. You can also use 2.5D EM simulation by placing a high resistivity layer just above and below your conductors and with this you can see the electric field; I have not used this for this application, just fooled around with it.
If you have HFSS and ePhysics you can perform thermal simulations. I have used this for verifying thin film loads.