Choosing a Type of Coupler

Type of Coupler

Couplers are very important when it comes to antenna arrays. Basically, the device samples a signal with a predetermined degree of coupling. In addition, they are passive devices meaning that, while there are separate input and output ports, they are often capable of working in either direction. While this process may sound simple, there are several options when it comes to picking out the right device for your array.

Directional

These power dividers have three accessible ports and one internal one. All this device does is sample the isolated signal. Typically, they are used when you need to measure reflected power. Once finished, the device feeds the signal back into the feedback circuitry.

Generally, these devices are optimized for the forward direction. When used this way, they will provide high levels of isolation and directivity. So while you can connect this device in reverse, you cannot use it in either direction. They show the reverse wave in the forward direction, and in the reverse direction, they show the forward wave.

Bi-Directional

This type of coupler has four accessible ports. The symmetrical design of this device gives it the ability to sample a forward and reverse current simultaneously. However, the coupled ports must either be matched or terminated for the readings to be accurate.

Dual Directional

Basically, this coupler combines two directional couplers with an input, output, and two internal isolation lines. In other words, it offers bi-directional coupler features but allows for two different isolation configurations. The biggest advantage of using this device is that applying a mismatched load to the forward and reverse signals will not affect the outcome of the measurements.

Couplers are important devices in RF systems. You can use them to measure both the forward and reverse signals, waves, and other crucial information. First, however, you must choose the right coupler when setting up your signal array.