Some questions about Wilkinson power divider

[Jacky Loh]

Recently, I am trying to design a 1:1 Wilkinson power divider using stripline. And I have some questions about it:
1. How to compesate the discontinuity, such as t-junction, bend, step....Is there some experence about it ?
2. I can have low VSWR at input port at f0(center frequency), but I can not have low VSWR at output ports at the same time. Meanwhile, the S23 at f0 is also not very low. As I konwn, these quantities of an optimized Wilkinson power divider can be very low at f0. I have no idea what is wrong.
Could anybody give me some hints? Thanks!!
PS: I upload some pictures about my model. And I used HFSS to simulate.

 

[jayce3390]

Your issue with S23 : could you give the value of the resistor you put between 2 and 3. This resistor provides the isolation.
And give ports 2 & 3 impedance.

 

[Jacky Loh]

Your issue with S23 : could you give the value of the resistor you put between 2 and 3. This resistor provides the isolation.
And give ports 2 & 3 impedance.

My design is a 1:1 Wilkinson Power divider. The input port is 50ohm. The two branchs is 70.7ohm. And the outputs are also 50ohm. The resistor is 100ohm.
The impendance are calculated by TXLINE.

 

[toonafishy]

upload your hfss file so we can look at it

 

[VSWR]

The 100 ohm resistor shall be located at the end of the 70.7 ohm transmission lines. It seems to be incorrectly located about 20-30° from this point.

 

[lovetm]

you can move the position of resistor and change the length of the 70,7 ohm

 

[biff44]

you can move the position of resistor and change the length of the 70,7 ohm

I would disagree with that. Your isolation will suffer.

 

[Jacky Loh]

you can move the position of resistor and change the length of the 70,7 ohm

I would disagree with that. Your isolation will suffer.

1. Could you tell me which position of resistor is best?
2. And how to locate the 1/4 lamda of 70.7ohm transmission line? because there is a T-juction from input to two outputs. I have no idea how to choose the reference plane.
3. Need I compensate the bend and T-juction discontinuities? And how to compensate?
Thank you veru much!

 

[biff44]

well, you have hfss. Just run the simulation, and move the location of the resistor closer and closer to the step in impedance. If the 70 ohm sections are pretty close to 90 degrees at f0, you will probably end up with the resistor right at the step transitions.

Keep your eye on S11, S22, S33, and S32 during your "optimization"

 

[lovetm]

maybe the microstrip following the resistor is too long,the signals of two terms couple to each other