A hybrid coupler is a four-port directional coupler that is designed to split power equally. You can find both 90- and 180-degree hybrids. Unlike standard couplers, there is no 45-degree hybrid. Therefore, you need to know about the two types of hybrids and how to get them to accomplish your task before building a project.
The 180-degree coupler category includes the rat-race and waveguide magic tees. The rat-race coupler tends to be the more popular option. When shopping for this type of coupler, consider the impedance before purchasing one.
These include the Lange, branchline, overlay, edge, and short-slot couplers. The branchline is the most popular 90-degree hybrid coupler. When shopping for this type of coupler, think about your impedance requirements and bandwidth.
Make a 180-Degree Coupler From a Branchline
In some applications, such as with a monopulse comparator, 180-degree couplers complicate your project’s layout. The good news is that you can get the same result by adding a section to a standard branchline coupler. This will lengthen the input wavelength, therefore altering the impedance. The result is a 180-degree function where a rat-race coupler doesn’t work. If you are shopping for rat-races and cannot find one, this method is also a good option.
Use Back to Back Couplers for an RF Crossover
By stacking hybrids, you can establish a four-port setup that provides isolation for two RF paths. You should only try this if there is room, and you don’t need a lot of bandwidth. If you are shopping for an RF-RF crossover and can’t find one, this is an option.
Hybrids are a popular type of coupler. They are designed to create an equal power split in a four-port system. You can use them in a lot of applications if you get the proper option. These tips will help you choose the right coupler and make modifications to your purchase if necessary.