RF Switch: Features, Applications, and Manufacturers

RF switches are indispensable for signal routing in communication systems. This article provides an in-depth overview of their functionality, applications, and popular manufacturers.

RF switches are used in many applications, including Tx/Rx switching and automation testing of simultaneous multiple devices. They are also used in multiple redundant systems found in critical applications such as VSAT Hub stations (MUX switch over units, modem switch over units, LNA switch over units, RF Power amplifier switch over units, etc.), for switching between different frequency bands, and so on.

They are used in all wireless technologies, e.g., WLAN, WiMAX, GSM, CDMA, HSPA, LTE, satellite, VSAT, zigbee, etc. PIN diodes and FETs are usually used for switch design.

Figure mentions Single pole double throw switch (RF switch) used to couple single antenna for both Tx and Rx path.

Above figure describes LNA Switch over unit designed using RF switches and used in VSAT Hub station. This switch-over unit allows two LNAs to be in operation in hot standby mode. Hence, in case of failure of one LNA, another will be automatically brought back into the circuit.

A modem switch-over unit is also a very useful system used in a VSAT hub station and is connected with multiple modems. Out of these, some are in the circuit, and one will be in hot standby. In case of failure of one of the normal in-circuit modems, the switch allows the standby modem to take control and replace the faulty modem, hence preventing loss of traffic operations for an extended time. For example, 8+1 modem switch-over units are connected with 8 normal in-circuit modems and 1 standby modem.

IF switches are used in the modem as a normal modem operates either around 70MHz or 140MHz. Similarly, up converter, down converter, and power amplifier switch-over units are in use.

These switch-over units will have small microcontroller software to continuously check all the devices form c contacts to determine a healthy condition and take action accordingly.

Similarly, RF switches are in use in production (manufacturing) testing wherein multiple devices (WLAN router, LTE router etc.) are to be tested using single RF VSG (Vector signal generator) and RF VSA (vector signal analyzer). In this type of setup, one by one device are brought into the circuit with VSG and VSA automatically using RF switch and testing need to be preformed and test log is to be recorded in the system.

RF Switch Manufacturers | RF Switch Vendors

Following are a few of the popular RF switch manufacturers:

1. Dow-Key Microwave Corporation
2. JFW industries
3. Analog devices
4. National Instruments
5. Skyworks Solutions Inc.
6. Agile Microwave Technology Inc.
7. Agilent technologies

Conclusion

RF switches ensure seamless signal routing, playing a pivotal role in modern RF applications.