Since the power sensor is one of the most important RF measurement tools, it is essential to be able to choose the right sensor for every application. Now, just like with every technology, there are various options available, each of which will have its various advantages and disadvantages. But with every choice there are claims and statements guaranteeing better performance than any other, so the process of selecting isn’t always an easy one. The heart of every sensor is crucial, and this is measured using any one of three common technologies – Thermocouple Sensor, Diode Sensor or a receiver.
Thermocouple sensors work die to the temperature difference between two metals which creates a voltage. This type of sensor gives a correct average power for different types of signal formals, without getting affected by wave shape or signal distortion. This type of peak power sensor system is usually used in systems which have complex modulation formals!
Diodes allow energy of high frequency to get converted to Dc, but using the non linear relationship between the change in voltage and change in current. This type of sensor is highly used for applications that need high sensitivity when it comes to measurements, as they have a range from –70 to –20 dBm. They also are usually chosen for radar test equipment which needs a fast reading, as thermocouple sensors allow a comparatively slower rate of measurement.
Advantages and disadvantages
The main advantage of thermocouples is that they can provide accurate readings for almost each and every type of signal. Another advantage to this source of power is the relationship between change in voltage and change in power, which allows accurate power readings. Also this type of source has a very high resistance to burnout. On the other hand, a diode sensor is rather easy to construct and use. Since it requires few components, it is also more cost effective for a company. Diode sensors also provide a much faster reading than thermocouple sensors, which is why they are selected for applications which require fast readings.
Any sensor however does come with some disadvantages of its own. Since the change in voltage and change in power due to temperature change are dynamic, it takes some time before the theremocouple sensor can give a reading or measurement. Because of this, thermocouple sensors have a slow rate of measurement. Also the dynamic range of these sensors is typically between -35 dBm to +20 dBm. The one major disadvantage of the diode sensor is that major distortions come into play once it outside the normal range. Also if the path length in this type of system is very long, there can be phases of weak signal.
“The above blog is written by a third party and is only for informative purposes. It does not reflect Ranatec’s position with regards to the provided information.”