Microwave switch, also known as RF switch, can control the conversion of microwave signal channel. An RF (radio frequency) and microwave switch is a device to route high frequency signals through the transmission path. RF and microwave switches are widely used in microwave test systems for signal routing between instruments and DUTs. Today, let's learn the basics of RF switches.
performance parameter
RF and microwave switches can send signals efficiently in the transmission path. The function of such switches can be characterized by four basic electrical parameters. Although many parameters are related to the performance of RF and microwave switches, the following four parameters are considered to be critical because of their strong correlation:
Isolation
Isolation degree is the attenuation degree between the input and output of the circuit. It is an index to measure the effectiveness of the switch cut-off.
insertion loss
Insertion loss (also known as transmission loss) is the total power lost when the switch is in the on state. As the insertion loss can directly lead to the increase of system noise figure, the insertion loss is the most critical parameter for designers.
Switching time
Switching time refers to the time required for the switch to change from "on" state to "off" state and from "off" state to "on" state. This time can reach the microsecond level of high-power switch and the nanosecond level of low-power high-speed switch. The most common definition of switching time is the time from when the input control voltage reaches 50% to when the final RF output power reaches 90%.
Power handling capacity
In addition, the power handling capacity is defined as the maximum RF input power that the switch can withstand without any permanent electrical performance degradation.
