wilkinson splitter combiner

Thingking of 2-way equal wilkinson power splitter/combiner and setting port 1 input(output),port 2 output(input), port 3 output(input)

1. I just know the banlance resistor is 100Ω, but how to get this value by mathematic formula?
2. All these three ports are matched. Looking into port 1, I can understand why it is matched ( port 2 resistor and port 3 resistor at joint are the same 2Z0, and 2Z0//2Z0=Z0). But I can't understand why it is matched looking into port 2 or port 3?
3. Why say the balance resistor provide good isolation? How to compute?
4. If power P enters into port 1, I know the power of port 2 and port 3 are the same, P/2. But if power P enters into port 2, how to compute the power of port 1, port 3, and balance resistor?
5. If port 1 mismatch, how to compute the power consumed by the balance resistor? If port 2 or port 3 mismatch,how to compute the power consumed by the balance resistor?

If possible, Please give me detail information. These questions puzzeled me many days. Many thanks!
My email is: sunstar16@163.com

Hi Sunstar

Have a look at the Mini Circuits Appl note AN10006: Understanding power splitters
It will answer your questions I assume. They have much more interesting appl notes......... start from their homepage.
http://www.minicircuits.com/appnote/an10006.pdf
rgds

Mike

you can also refer to pozar's microwave engineering book

these are all simple questions.
you should pick up in theroy of microwave solid circuits .
almost general basic books you will find your answers.
you can see some chapters in this book-----
microwave transistor amplifier Analysis and Design by Guillermo Gonzalez, Ph.D.
good luck.

Hey

Many of your questions can be answered using Even -Odd mode analysis. This is dealt with in Pozars book. You should read this section. This is the key to understanding the wilkinson design and behavior.

Regards

Trust me! You can refer the chap 7-power divider and directional couplers of "microwave engineering" third edition by Pozar. Then you will get many senses about it.

i want to design a wilkinson splitter. all i know are these formulas: Zw=50Ohm, the splitted part is sqrt2*50 Ohm and R=2Zw

how can i get the length of the microstrip line.
i know the basics about this splitter, but how to define each line i'm not sure.
how long is a λ/4 line in this case and what about the thickness?

For a single section splitter, the two "splitted" lines that lead to either end of the 100 ohm resistor have and impedance given by

Z = √(50 * 100) =70.7 ohms

This is because each of them is a quarter wave transformer. At the two outputs, each output is loaded with 50 ohms. At the single input, you want the total impedance to be 50 ohms, which you get from the two lines provided 100 ohms in parallel with another 100 ohms, so the input is matched.

In other words, each of the "splitted" lines is a 100 ohm to 50 ohm quarter wave transformer.

Here are the relevant Wilkinson divider pages from Pozar's Microwave Engineering.

now i want to design the splitter with serenade sv. my frequency range is 1 -2.5GHz, so i take the center frequeny, right?
but to geht the width and electrical length the program asks for impedance and phase.
what to put in for impedance i know, but about the phase i'm not sure.
if i say i want a 0° phase, the length of the transmission line is zero.

get a λ/4 line i have the impedance of 70.7Ω, but it is important how long and thick my microstripline has to be.

right now, i have no clue

quarter wave length mean phase=90.however , the length is too long for my operating frequency of 900MHz.is there any way i reduce it maybe lamba/40?

Hi

You can use lumped components instead, to make QW lines. This is used a lot a low frequencies or with small circuits.

Regards

hello friends I can use a power splitter to combine amplifying pallets