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Copyright © 2018 Nevada RF, All Rights Reserved
2-Way and 3-Way In-Phase High Power Combiners
ColdRF™ Heat Displacement Technology
No Internal Resistors or Terminations
Excellent Phase/Amplitude Balance, Return Loss & Isolation
Fast Quotation and Delivery to Custom Requirements
Click here to download the ColdRF™ datasheet
ColdRF™ Heat Displacement Technology
No Internal Resistors or Terminations
Excellent Phase/Amplitude Balance, Return Loss & Isolation
Fast Quotation and Delivery to Custom Requirements
Click here to download the ColdRF™ datasheet
Why is this a big deal?
ColdRF™ solutions relocate the normal internal heat dissipation to an external 50 ohm load conveniently connected by coaxial cable. On average, 90 percent of the thermal challenge is moved to a convenient cold plate location, an invaluable benefit when combining signals of different frequencies which would burn out the loads in conventional combiners. The model NRF-0210 (pictured at right) has been tested for 80 hours with two 400 watt CW inputs (3100 and 3500 MHz), with neither damage nor degradation. See the ColdRF™ FAQ for more information.
ColdRF™ solutions relocate the normal internal heat dissipation to an external 50 ohm load conveniently connected by coaxial cable. On average, 90 percent of the thermal challenge is moved to a convenient cold plate location, an invaluable benefit when combining signals of different frequencies which would burn out the loads in conventional combiners. The model NRF-0210 (pictured at right) has been tested for 80 hours with two 400 watt CW inputs (3100 and 3500 MHz), with neither damage nor degradation. See the ColdRF™ FAQ for more information.
ColdRF™ Combiners
Advantages & Applications
Normal combining of power amplifiers
Combination of unrelated (uncorrelated) high power inputs
High power work in small spaces with remote heat sinking
EW
EMI/EMC
Lab instrumentation
Fast turnaround on custom designs
Normal combining of power amplifiers
Combination of unrelated (uncorrelated) high power inputs
High power work in small spaces with remote heat sinking
EW
EMI/EMC
Lab instrumentation
Fast turnaround on custom designs
Frequently Asked Questions
Q. Is Nevada RF a new company?
A. Officially, but we have been providing specialty components to agencies and other customers since 2014.
Q. What do you do or make?
A. We are concentrating on high power combiners with uncompromised ability to combine uncorrelated signals.
Q. What do you mean by uncompromised?
A. Our ColdRF™ in-phase combiners can handle as much uncorrelated power in combining mode as they do input power as a splitter.
Q. Can you elaborate?
A. Think about an ideal 2-way Wilkinson splitter/combiner as an example. As a splitter, input 100 watts and you'll get 50 watts from each of the two ports on the other side. As a combiner, input identical 50 watt signals into those two ports and you'll get a 100 watt sum. But inside typical in-phase combiners are one or more resistors from port to port. The higher the frequency and the higher the power, the worse the RF performance of those resistors. This is of little consequence when splitting, when combining signals that are identical or nearly so, or when combining low level inputs. But consider a case of a 50 watt input to one combining port and no input to the other. By reciprocity, any such combiner will deliver 25 watts to its common port and 25 watts to the internal resistor(s). Now apply two 50 watt inputs at different and unrelated frequencies. Half of each input will get to the common port; the other half of each is dissipated internally. Some companies sell splitters with no internal loads for very high power splitting applications simply because the resistors cannot be rendered and/or connected with acceptable high frequency performance. As an exercise, look up 100 watt RF resistors and look at their undesirable parasitic effects at microwave frequencies!
ColdRF™ combiners do away with the node-to-node resistive elements of normal in-phase microwave combiners. Instead, we add a port for a 50 ohm load to ground, the implications of which are very significant, namely that the necessary dissipation is moved from the actual combining location to a 50 ohm load secured at a convenient cold plate. Imagine the combiner being in a tight space with a small cable from its termination port to a load 3, 30 or 300 feet away! On average, 90 percent of the total dissipation is in the external load, the remainder in the combiner itself. Look at catalogs for high power combiners and you may, for example, find a 100 watt component able to split that much power but only able to combine arbitrary five watt inputs. That power limit may not be acknowledged in ads and catalogs, at times implicitly stated using maximum load VSWR. Call a combiner company and ask about the maximum allowed input power to one of the input ports with the others terminated. Multiply that number by the order of the combiner (2 for 2-way, etc.) and you'll find out the real ability of the combiner to handle power. And you'll still have to sink the heat away at that combiner's location.
Q. Are the external load and cable a requirement?
A. No, but they are part of the novel ColdRF™ solution for combining uncorrelated signals of very high power. For lower power operation you can simply attach a 50 ohm load to the respective port and leave it there indefinitely.
Q. Will the combiner be damaged if I forget to attach a load?
A. Not at all. Operating as a splitter it will work fine as long as the loads have very low VSWR; as a combiner of identical inputs it will work well; with different or partially uncorrelated input it will have poor return loss and isolation.
Q. Is Nevada RF a new company?
A. Officially, but we have been providing specialty components to agencies and other customers since 2014.
Q. What do you do or make?
A. We are concentrating on high power combiners with uncompromised ability to combine uncorrelated signals.
Q. What do you mean by uncompromised?
A. Our ColdRF™ in-phase combiners can handle as much uncorrelated power in combining mode as they do input power as a splitter.
Q. Can you elaborate?
A. Think about an ideal 2-way Wilkinson splitter/combiner as an example. As a splitter, input 100 watts and you'll get 50 watts from each of the two ports on the other side. As a combiner, input identical 50 watt signals into those two ports and you'll get a 100 watt sum. But inside typical in-phase combiners are one or more resistors from port to port. The higher the frequency and the higher the power, the worse the RF performance of those resistors. This is of little consequence when splitting, when combining signals that are identical or nearly so, or when combining low level inputs. But consider a case of a 50 watt input to one combining port and no input to the other. By reciprocity, any such combiner will deliver 25 watts to its common port and 25 watts to the internal resistor(s). Now apply two 50 watt inputs at different and unrelated frequencies. Half of each input will get to the common port; the other half of each is dissipated internally. Some companies sell splitters with no internal loads for very high power splitting applications simply because the resistors cannot be rendered and/or connected with acceptable high frequency performance. As an exercise, look up 100 watt RF resistors and look at their undesirable parasitic effects at microwave frequencies!
ColdRF™ combiners do away with the node-to-node resistive elements of normal in-phase microwave combiners. Instead, we add a port for a 50 ohm load to ground, the implications of which are very significant, namely that the necessary dissipation is moved from the actual combining location to a 50 ohm load secured at a convenient cold plate. Imagine the combiner being in a tight space with a small cable from its termination port to a load 3, 30 or 300 feet away! On average, 90 percent of the total dissipation is in the external load, the remainder in the combiner itself. Look at catalogs for high power combiners and you may, for example, find a 100 watt component able to split that much power but only able to combine arbitrary five watt inputs. That power limit may not be acknowledged in ads and catalogs, at times implicitly stated using maximum load VSWR. Call a combiner company and ask about the maximum allowed input power to one of the input ports with the others terminated. Multiply that number by the order of the combiner (2 for 2-way, etc.) and you'll find out the real ability of the combiner to handle power. And you'll still have to sink the heat away at that combiner's location.
Q. Are the external load and cable a requirement?
A. No, but they are part of the novel ColdRF™ solution for combining uncorrelated signals of very high power. For lower power operation you can simply attach a 50 ohm load to the respective port and leave it there indefinitely.
Q. Will the combiner be damaged if I forget to attach a load?
A. Not at all. Operating as a splitter it will work fine as long as the loads have very low VSWR; as a combiner of identical inputs it will work well; with different or partially uncorrelated input it will have poor return loss and isolation.