Directional couplers are significant as they help sample Radio Frequency(RF)signals for measurement, processing, and support analysis. The device’s degree of coupling and directionality determines how a signal is injected. The passive nature of such gadgets enables the reverse direction operation of such equipment. Listed below are the recommended specifications for such appliances.
Directivity
A directional coupler can isolate the signals traveling in opposite directions. Power termination at the coupled port and at the isolated port is rationed. However, for a three-port coupler, power connections in the forward direction and the one containing the input and output ports are made. A higher directivity ensures better performance of a coupler, and the opposite is true. The computation of this characteristic is on the reversed isolation and isolation measurement basis.
Coupling Coefficient
The coupling factor measures the ratio between the power at the input to the one at the coupled port. The attribute ensures the correct coupler termination at all ports to estimate accurately. This prime feature of a directional coupler ensures the output power on the port with coupling is proportional to the one in the direct path. The output, in this case, is connected to instrumentation like an oscilloscope. The dangers of overloading the equipment, in this case, are significantly reduced.
Insertion Loss
The installation of the coupler onto the main route of power transmission causes loss of power. The input power to the output port is significantly reduced compared to the amount which reaches the isolated and the coupled ports. In the case of rf couplers, the insertion of a given device into the transmission line contributes to power reduction. This is also defined as the power ratio of an inserted device to the input power at the output.
Voltage Standing Wave Ratio
This ratio is essential and ranges from 1 to an infinite value. It expresses the quantity of reflected energy at the device input. A directional coupler typically has a value less than one, indicating energy bouncing back due to reflection. Having a value less than one is an indication that all the energy does not pass through. Such devices have a specified value that facilitates their optimum performance according to the application.
Average And Rated Power
The average power of a continuous wave for one-way transmission ensures that the couplers can handle power under the matched load. The maximum input power for such gadgets is in watts, both for pulsed input signals and continuous waves. Specification of the correct quantity that can be handled without physical damage or performance degradation is enabled for the users.
Directional couplers are utilized in radio frequency RF as well as in microwave circuits. The functions of such devices include power monitoring, leveling, transmission, and reflection applications. Properly designed directional couplers facilitate the coupling from one transmission line to the other.
