- Buyers Guide
Military Microwaves Supplement
A coaxial circuit insertion (bypass) function relay provides a cost-effective approach for high performance wireless communications equipment as well as automatic test equipment and a variety of test and monitoring instrumentation. The relay's switching function allows a circuit element to be bypassed or inserted as required without shorting the element in the bypassed state. This type of switching is accomplished typically using two SPDT relays.
The model RCT-CP1B4 relay uses surface-mount technology (SMT) and requires up to 75 percent less actuating current than conventional SMA connectorized relays without sacrificing RF performance. The relay operates over the frequency range from DC to 4 GHz and has a nominal characteristic impedance of 50 W. The operating voltage is 21.5 to 26.5 V DC over the -40¡ to +85¡C temperature range with a nominal operating current of 83 mA at 24 V DC and 25¡C. At 25¡C, the relay actuation voltage is specified at 19 V DC (min) and the dropout voltage is 2 V DC. Switching time is 10 ms (max) at 24 V DC and 25¡C. The switching actuation is fail-safe to bypass with a break-before-make configuration. The relay's minimum lifetime is 106 cycles. Table 1 lists key relay specifications. The relay is housed in a nickel-plated aluminum housing measuring 1" ´ 0.74" ´ 0.41" high and is designed to be surface mounted directly to a microstrip circuit board. The preformed gold-plated gull-wing-style RF contacts provide a smooth and consistent RF transition for various types of microstrip boards. The relay outline is shown in Figure 1 .
This mechanical configuration allows the input/output pins to be soldered directly to the microstrip circuit traces in an SMT configuration. The results of this mounting configuration are low procurement and installation costs due to the elimination of connectors and interconnect cabling, and low insertion loss due to the elimination of the connector electrical transitions. Figure 2 shows the relay's typical insertion loss and Figure 3 shows the typical SWR.
The subminiature SMT circuit insertion relay is fully coaxial. Depending upon the microstrip board and launch geometry, the relay is capable of RF performance up to 12 GHz. Applications for this relay include microwave radios; compact switch matrices; digital and RF test equipment; and low and medium power switching of amplifiers, attenuators and filters.
RelComm Technologies Inc.
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