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Reflective PIN Switch

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EVlab:
I want to connect a YIG-oscillator to a reflective PIN switch.

Can someone give a hint (pros/cons) of either using an isolator or a 0dB attenuator to protect the YIG if the switch is turned off e.g. open position?

Best, Simon

KE5FX:
The 0 dB attenuator (whatever that is) won't do much of anything.

The isolator will present a load near Zo (usually 50 ohms) no matter what's connected to its output port.  They're not usually used to protect the YTO, though, but to improve output level flatness (and sometimes frequency stability) and provide a better port match for a subsequent stage (typically a mixer.)  The output amplitude of a typical YIG oscillator isn't high enough to be a threat to the output device when unterminated.

uncle_bob:

--- Quote from: EVlab on May 01, 2016, 08:32:54 am ---I want to connect a YIG-oscillator to a reflective PIN switch.

Can someone give a hint (pros/cons) of either using an isolator or a 0dB attenuator to protect the YIG if the switch is turned off e.g. open position?

Best, Simon

--- End quote ---

Hi

What are you trying to do? Put another way, what does your system design look like?

Are you trying to keep the YIG from "chirping" when the switch is thrown?

Are you trying to improve the isolation of the switch?

There are lots of possible things you may be worried about. A bit more information might allow us to give better advice.

Bob

EVlab:
I want to combine two YIG oscillators to one common output. Only one single YIG should operate at a given time. The YIG's cover two different frequency ranges. Thus I will use a two port PIN switch to select between the two YIG's and have one single output port providing frequency coverage over both YIG's.

The PIN switch is reflective and I'm not sure if one YIG will get damaged, if the PIN switch is in open position.

One can disable the not used YIG, but there will be some overlapping during transition when switching from one to the other.

Best, Simon

uncle_bob:

--- Quote from: EVlab on May 01, 2016, 05:29:43 pm ---I want to combine two YIG oscillators to one common output. Only one single YIG should operate at a given time. The YIG's cover two different frequency ranges. Thus I will use a two port PIN switch to select between the two YIG's and have one single output port providing frequency coverage over both YIG's.

The PIN switch is reflective and I'm not sure if one YIG will get damaged, if the PIN switch is in open position.

One can disable the not used YIG, but there will be some overlapping during transition when switching from one to the other.

Best, Simon

--- End quote ---

Hi

Simple answer - no you do not need to worry about the YIG going up in smoke with the designs I have seen. Is there one out there that could have a problem? Who knows. A 3 db pad between the switch and YIG will likely take care of any weird part that does have a problem.

Shutting off the un-used YIG does have the benefit of getting rid of a spurious signal in your system. No switch is ever ideal. Isolation will be "interesting" with a YIG driving a reflective switch ( = you don't know the voltage at the switch). Will this be a problem in your system? Again, a "that depends" sort of thing.

Bob

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