2022-09-10 17:20 Status: # rat-race coupler Used for [mixers](mixers.md) and [phase shifters](Phase%20shifter.md). ![Pasted image 20220910172232](attachments/Pasted%20image%2020220910172232.jpg#invert) [^1] ![Pasted image 20220910172812](attachments/Pasted%20image%2020220910172812.jpg#invert) ![Pasted image 20220910172816](attachments/Pasted%20image%2020220910172816.jpg#invert) ![Pasted image 20220910172930](attachments/Pasted%20image%2020220910172930.jpg#invert) ![Pasted image 20220910172939](attachments/Pasted%20image%2020220910172939.jpg#invert) [^2] ![636541177488041051-ratrace](attachments/636541177488041051-ratrace.gif)  "the switched loads have to present high reflection coefficients" ## Circuit Operation Look at the distances around the circle. ![](attachments/rat-race%20coupler-2.png#invert) You can control how much of a signal is sent one way or another based on the ratio of the two impedances you are dividing into (assuming they are matched to the input giving a VSWR of 1:1) This takes one signal, then without reflection generates a true and its complement for a differential output. This means it can be used as a balun! [^3] --- # References [^1]: [Microwaves101 | Rat-race couplers](https://www.microwaves101.com/encyclopedias/rat-race-couplers) [^2]: [RF and Microwave PCB Design - Part 5: Couplers - YouTube](https://www.youtube.com/watch?v=Yg0diblMQBI)