Coaxial Switching Products - Radiall - #10

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Graphique 1.cdr table.main {} tr.row {} td.cell {} div.block {} div.paragraph {} .font0 { font:7.00pt "Arial", sans-serif; } .font1 { font:8.00pt "Arial", sans-serif; } .font2 { font:9.00pt "Arial", sans-serif; } .font3 { font:12.00pt "Arial", sans-serif; } .font4 { font:13.00pt "Arial", sans-serif; } .font5 { font:17.00pt "Arial", sans-serif; } .font6 { font:8.00pt "Tahoma", sans-serif; } SWITCHING PRODUCTS TECHNICAL INFORMATION 9) RAMSES Concept An innovative new system has been designed for constructing electromechanical coaxial RF switches with increased long-term reliability. The RAdiall 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 résistance reliability over time. In addition, the unique internai construction makes the switches cost-competitive with traditional switches. Friction Effects The unique design of RAMSES is based on the réduction of friction, which minimizes particle deposits that can interfère with the transmission of lower frequency signais (up to 3 GHz). This particle élimination effect is particularly important for télécommunications applications that are currently in the 900 MHz and 2 GHz régions. In addition, the design involves fewer components than other microwave switches, making it easier and quicker to assemble. Thèse savings directly relate to lower cost for improved performance. Many of the existing coaxial electromechanical switches also are able to function mechanically for 10 million opérations. But the reliability and quality of the electrical contact can seriously dégrade during that lifetime. In gênerai, thèse traditional switches operate by moving a rectangular switching blades 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. Thèse 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. Thèse 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 (3GHzandbelow). A new actuator Configuration To eliminate this problem of increased insertion loss in the contacts, RAMSES devices incorporate a patented system compressing 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. Thèse blades impose a rectilinear motion on the switching pusher, suppressing both friction and the production of particles inside the RF cavity. The unique (b) RFlineclosed Figure 1 : Conventional switch contacts afterone million cycles system is extremely small and can be used in ail of the RAMSES séries switches. Figure 2 shows a cutaway view of a RAMSES coaxial switch displaying the actuator mechanism. Asecond improvement involves a new rectilinear actuator design using high energy magnets and a switching performance in relation to its size. The system is used in the production of both fail-safe and latching actuators, depending on how it is applied in the switch. The actuator system also produces sticking forces that far exceed those of traditional actuators; that is, either 500g locking forces or 300 to 800g current forces for a power consumption of 100 mA at 28V. The new actuator has the added advantage of very low magnetic leakage, allowing actuators to be used in close proximity to one another without performance dégradation. Finally, the use of a dry, solid lubricant and the control of friction areas produce an For more technical information, consult us/E-mail : USA : rfswitchusa@radiall.com /Rest ofthe world : switchingproducts@radiall.com lntro-8