Switches control the presence and direction of signals in high-frequency systems, ideally with as little of their own electrical contributions as possible. RLC Electronics helps to minimize those contributions by building their extensive multi-throw switch technologies into compact modules, along with other components when required. By integrating multiple switches and/or other components into a single miniature package, not only can physical size be saved, but the insertion loss and phase distortion of unnecessary connectors and coaxial cables can be avoided. RLC Electronics builds the modules based on the use of single-pole, double-throw (SPDT) switches from DC to 65 GHz; single-pole, three-throw (SP3T) to single-pole, six-throw (SP6T) switches to 40 GHz; and single-pole, seven-throw (SP7T) through single-pole, twelve-throw (SP12T) switches to 18 GHz.
The integrated switch modules (see figure) can be configured in an almost endless variety of configurations, with supporting functions such as power division or filtering included in the module housing. Different combinations of switches can be used, depending on the number of throws and power-handling capabilities needed. All of the critical impedance-matching between functions and components is already handled within the module housing.
These compact, switch-based modules allow system-level architects to rethink their designs, since they can include various other functionssuch as couplers, power dividers, filters, and interconnecting cableswith the switch assemblies. The performance of the assembly as a whole can be optimized, with interconnecting cable lengths minimized for minimal additional passive loss, time delays, and phase distortion. For example, for applications requiring tight amplitude and/or phase matching between or among different signal paths, these integrated switch assemblies enable precise control of the amplitude and phase tolerances of different signal paths (even over wide operating temperature ranges). These integrated switch modules, which are available with a number of different control optionsincluding failsafe and latchingare simply powered and controlled from a single connector.
As an example of this module integration approach, a multi-switch module was developed for an application in which an RF power source would be switched between a pair of antennas, at the same time selecting a signal path with a fixed delay line when necessary. This antenna beam-steering application called for relatively fast switching speed with moderate power-handling capability and minimal insertion loss for all signal paths. The 50-O switch module featured failsafe operating mode with indicators, and was rated for 450 W average power and 3.5 kW peak power with 30-ns switching time between switch states.
Designed for use from 400 to 500 MHz, this integrated switch module exhibits impressively low insertion loss, with 0.2 dB maximum insertion loss from the RF port to antenna array 2 and 0.3 dB maximum insertion loss from RF port to antenna array 1. As a measure of the tight control achieved in the integration of components within the module housing and the manufacturing process, the phase repeatability is within 2 deg. from unit to unit when evaluating the same signal path from unit to unit.
This integrated switch module features 35-dB minimum isolation between ports with maximum VSWR of 1.20:1. The rugged switches used in the module are rated for a minimum of 1 million switching operations, and draw maximum current of 220 mA per switch at +28 VDC. The module housing measures 5.25 x 3.42 x 2.50 in. less connectors, and is just one example of the switch-based solutions possible with this modular integration approach.