An Innovative System for Coaxial RF Switches: RAMSES

Previously, we discussed the basics of an RF & MW electromechanical switches and switching technologies. If you have not read it yet, you can reach the article via https://www.evtechnews.us/post/rf-microwave-electromechanical-switches


With this article, we explained Radiall's patented switching concept.


An innovative system has been designed for constructing electromechanical coaxial RF switches with increased long-term reliability. RADIALL’s Modular System for Electromechanical Switches (RAMSES) is a patented concept that enables microwave coaxial switches to be produced with a typical operating life of 10 million cycles while suffering no decrease in contact resistance reliability over time. In addition, the unique internal construction makes the switches cost-competitive with traditional switches.


The unique design of RAMSES is based on the reduction of friction, which minimizes particle deposits that can interfere with the transmission of lower frequency signals up to 3 GHz. This particle elimination effect is particularly important for telecommunication applications that are currently in the 900 MHz and 2 GHz range. In addition, the design involves fewer components compared to other microwave switches, making it quick and easy to assemble.


These savings directly relate to lower costs for improved performance. Many of the existing coaxial electromechanical switches also are able to function mechanically for 10 million operations. However, the reliability and quality of the electrical contact can decrease over the life cycle.


In general, these traditional switches operate by moving a rectangular switching blade section inside a rectangular cavity. The blades are linked with pushers constructed of dielectric material that travel inside an access hole between the RF cavity and switch actuator. The pushers are directed by dielectric material guides. These dielectric parts rub on the blades and inside the access hole and generate isolating particles in the RF cavity that pollute the electrical contacts and ultimately cause running defects.


Figure 1 shows the build-up of minute dielectric particles on a set of conventional switch contacts after one million cycles. These defects are not particularly noticeable at very high frequencies since the contact is established by a capacitive effect. However, the insertion loss of the contacts increases considerably at lower frequencies, below 3 GHz.


To eliminate this problem of increased insertion loss in the contacts, RAMSES devices incorporate a patented system. This system compresses two parallel blades suspended from a bearer, which enables the guiding and positioning of the commutation blades to be accomplished entirely outside the RF cavity. These blades impose a rectilinear motion on the switching pusher, suppressing both friction and the production of particles inside the RF cavity. The unique system is extremely small and can be used in all of the RAMSES series switches.






Figure 2 shows a cutaway view of a RAMSES coaxial switch displaying the actuator mechanism. A second improvement involves a new rectilinear actuator design using high-energy magnets and a switching performance with its size.





The system is used in the production of both failsafe and latching actuators, depending on how it is applied in the switch. These actuators are either 500 g locking forces or 300 to 800 g current forces for a power consumption of 100 mA at 28 V.



The new actuator has the added advantage of very low magnetic leakage, allowing actuators to be used close to one another without performance degradation. The use of a dry, solid lubricant and the control of friction areas provide an actuator life expectancy of over 50 million operations without defect when the temperature range exceeds -40° to +85°C.


RAMSES series switches have successfully survived tests of 10 million switching temperature cycles from -55° to + 85°C while demonstrating good contact resistance stability. Visual inspection of these switches after testing has indicated that the RF lines were free of much of the contamination found during similar tests on traditional switches. A comparison of the actual measured contact resistance obtained from monitoring both conventional and RAMSES switches using several parts that have already been actuated one million cycles is shown in figure 4 below. Although the conventional switch may not be considered a failure, its contact resistance has become unstable, thus degrading its reliability.


RAMSES Series

SPDT up to 50 GHz: PC Board - SMA - SMA 2.9 (K) - 2.4 mm - QMA - DIN 1.6/5.6


Radiall's RAMSES concept (which provides for a life span of 10 million cycles) offers a variety of options to meet customer needs from DC to 50 GHz. These switches are dedicated to all market applications including military, instrumentation, and telecommunications.




SPDT up to 18 GHz: N- TNC - BNC



They are commonly used for applications where high power handling capability is required in RF & Microwave systems up to 18 GHz.






DP3T and Terminated SPDT up to 50 GHz: SMA - SMA 2.9 (K) - 2.4 mm


Radiall’s RAMSES DP3T and Terminated SPDT switches offer excellent reliability, high performance, and operating frequencies from DC to 50 GHz. A full range of options is available within the RAMSES range to offer customers a complete solution.




DPDT up to 50 GHz: SMA – SMA 2.9 - 2.4 mm - QMA – DIN 1.6/5.6


Radiall's DPDT switches offer excellent reliability, high performance, and operating frequencies from DC to 50 GHz. Radiall's RAMSES concept guarantees a life span of 2.5 million cycles and provides a full array of options to respond to the needs of our customers.





DPDT up to 12.4 GHz: N - BNC - TNC



Radiall's DPDT switches offer excellent reliability, high performance, and operating frequencies from DC to 12.4 GHz. with a guarantee of a life span of 2.5 million cycles.





SPnT USB up to 40 GHz: SMA - SMA 2.9 (K)

Utilizing Radiall’s proven and patented RAMSES concept, Radiall integrated a mini-USB terminal on SP6T and SP8T switches for simplified use especially in test & lab applications.

Featuring an easy-to-integrate design, USB Coaxial Switches are delivered with a 1 meter long USB cable for power supply and switch drive. A soft front panel is provided to control the switches but commonly used software programming

platforms such as Visual Basic, C#, C++, LabVIEW and VEE are also compatible.


SPnT Terminated & Non-Terminated up to 50 GHz: SMA - SMA 2.9 (K) - 2.4 mm - QMA - DIN 1.6/5.6

Radiall offers reliable products, with shorter delivery times and competitive pricing. Excellent typical RF performance make RAMSES switches (40 GHz) ideal for Automated Test Equipment (ATE) and other measurement applications. These switches are suitable for defense, industrial, instrumentation and telecommunication applications.


SPnT up to 12.4 GHz: N - BNC - TNC



Radiall's R573 and R574 multithrow coaxial switches are offered in many configurations (over 40,000 possible combinations), including Terminated and non-terminated options.





SPDT Low PIM up to 18 GHz


RAMSES SPDT Low PIM switches are perfectly suited for RF test systems and test benches requiring excellent passive intermodulation performance up to 18 GHz; with a guarantee PIM performance of -160 dBc @ +43 dBm over a life span of 2 million switching cycles.




DPDT Low PIM up to 18 GHz

RAMSES DPDT Low PIM switches are perfectly suited for RF test systems and test benches requiring excellent passive intermodulation performance up to 18 GHz; with a guarantee PIM performance of -160 dBc @ +43 dBm over a life span of 2 million switching cycles. These products are specific to instrumentation and telecommunication applications.



SPnT Low PIM up to 18 GHz

RAMSES SPnT Low PIM switches are perfectly suited for RF test systems and test benches requiring excellent passive intermodulation performance up to 18 GHz; with a guarantee PIM performance of -160 dBc @ +43 dBm over a life span of 2 million switching cycles. These products are specific to 4G/LTE networks and instrumentation.



Thermal Vacuum Switches for Ground Segments

With more than 25 years of experience in the space industry, Radiall has developed a product offering that emphasizes reliability and performance. The latest addition to the range includes SPDT, DPDT and SPnT RF switches designed to operate in thermal vacuum environments.








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