Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

waveguide power combining, is it possible?

Status
Not open for further replies.

PG4I

Newbie level 4
Joined
Jul 25, 2014
Messages
7
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Location
Netherlands
Activity points
51
I am looking into combining two 1 kW waveguide magnetrons so the total output power is 2 kW.

I have tested a WR340 waveguide splitter to see if I can use it as a combiner. A test with the network analyzer shows good performance as a splitter but a 6 dB loss as a combiner. Coupling to the waveguide is done with coax to waveguide transitions. VSWR at the input ports is 2.6 which is already a 20% loss.

Next, a WR284 magic Tee was tested. Great port isolation, but the power at the sum (sigma) port is 3dB below the expected level.

Is it at all possible to do waveguide power combining?

Thanks
 

biff44

Advanced Member level 5
Joined
Dec 24, 2004
Messages
4,899
Helped
1,360
Reputation
2,716
Reaction score
1,039
Trophy points
1,393
Location
New England, USA
Activity points
36,861
a magic tee is a VOLTAGE vector combination device. in other words, if you have a signal at port 1, and another signal at port 2 that is the SAME AMPLITUDE AND PHASE....then almost all the power ends up at the SUM output port, and little of the power ends up at the ISOLATION port.

but you said you are using magnetrons? Are the two magnetron outputs at exactly the same phase? to get them to be the same phase, they have to be PHASE LOCKED somehow. If they are just free running, then they are non coherent, and will combined very differently.
 
Last edited:

PG4I

Newbie level 4
Joined
Jul 25, 2014
Messages
7
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Location
Netherlands
Activity points
51
Yeah I know what you mean... I am trying to have it working at low power and work from there. One signal source is a network analyzer which i have set to a 1 Hz span. The other is a signal generator which has a 1 Hz resolution. I guess even this setup won't work, unless you are lucky (because phase dependency is critical)?

Would there be any solution available when the 2 signal source differ in frequency?
 

biff44

Advanced Member level 5
Joined
Dec 24, 2004
Messages
4,899
Helped
1,360
Reputation
2,716
Reaction score
1,039
Trophy points
1,393
Location
New England, USA
Activity points
36,861
if the two signal sources are different frequencies, they will not be phase coherent and should incur a 3 dB combining loss. I keep meaning to do some optical wg combining experiments to see if there IS some way to spatially combine two incoherent signals with 0 dB loss....but I never get around to it. In my mind there SHOULD be a way of doing it, but so far everything I try is 3dB loss.
 

PG4I

Newbie level 4
Joined
Jul 25, 2014
Messages
7
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Location
Netherlands
Activity points
51
That's what I am seeing with the Magic Tee: a 3 dB loss when I move away from the coherent frequency! Thanks so far for your comments.

Regards,
Joop
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top