Hey guys,

I need to switch a 400-690 MHz signal. The signal is received in an antenna and go through the coaxial cable. The idea is switch the signal, turning it on and off (letting it pass or not) as necessary. I´m using a microcontroller, and I think in doing it with an optoacoupler or a transistor as switch. Anyone know some model of this components that can work well at this level of frequency?

Thanks!

 

I don't know for sure that an opto-coupler will work at those frequencies. Certainly there will be a substantial delay from input to output. Your garden variety transistor won't work well in this application at all. What is your next plan?

 

You can use PIN diodes for this, or an RF relay. Don't waste your time trying to use transistors or an optocoupler to switch your signal.

 

How about something like this:
https://www.minicircuits.com/WebStore/dashboard.html?model=HSWA2-30DR+

Might be able to find one with real leads if that is needed. Like this:
https://www.minicircuits.com/WebStore/dashboard.html?model=MSWA-2-20+

 

Hey guys,

I need to switch a 400-690 MHz signal. The signal is received in an antenna and go through the coaxial cable. The idea is switch the signal, turning it on and off (letting it pass or not) as necessary. I´m using a microcontroller, and I think in doing it with an optoacoupler or a transistor as switch. Anyone know some model of this components that can work well at this level of frequency?

Thanks!

Using transistor or pin diode may be possible, but there exists good IC for this purpose already. Ylli above has recommended the SPST switch chips from minicircuits. But it seems that you only need an SPST switch, so this chip works well:
https://www.qorvo.com/products/p/QPC6014
It has more than 50 dB isolation, also it is a absorptive switch, there is internal termination in the "OFF" status to keep the VSWR always low.

 

You can use PIN diodes for this, or an RF relay. Don't waste your time trying to use transistors or an optocoupler to switch your signal.

I did not find relay for those frequencies here in my living. I thought about PIN diodes but that was my plan B. Thanks!

How about something like this:
https://www.minicircuits.com/WebStore/dashboard.html?model=HSWA2-30DR+

Might be able to find one with real leads if that is needed. Like this:
https://www.minicircuits.com/WebStore/dashboard.html?model=MSWA-2-20+

I did not know these chips. I will give a good look at them, it seems exactly what I was looking for and solve the problem, really thanks!!

Using transistor or pin diode may be possible, but there exists good IC for this purpose already. Ylli above has recommended the SPST switch chips from minicircuits. But it seems that you only need an SPST switch, so this chip works well:
https://www.qorvo.com/products/p/QPC6014
It has more than 50 dB isolation, also it is a absorptive switch, there is internal termination in the "OFF" status to keep the VSWR always low.

Yeah, like I said above I didn´t know about these chips, it´s gonna be a great help, much easier than PIN diode and trasistors. Thanks!!

 

You may want to start with a simple Google of "coaxial RF Switches" taking note of the connectors used and their loss over a frequency range.

Ron