On Filter Subsystems

Filters are rarely used by themselves. They operate in a system and are therefore required to work with other components at their input and output. Since current microwave systems demand more performance in less volume, it becomes important to consider the synergistic relationship of the filter to the system, and to try to integrate it with other components.

Filters lend themselves to integration with other components. By integration of a filter with an amplifier or switch, the two components can be impedance matched for optimum performance to specification. Then the filter will not be tuned into a 50 ohms resistive load, but to the actual impedance it sees in operation. The result is better rejection, higher gain, lower VSWR, and flatter response. This is accomplished in less volume since housing walls and bulky interconnecting connectors can be eliminated.

At RS Microwave we are building subsystems of the following types:

Switched filter banks, using packaged GaAs switches, through 6 GHz. The assemblies are available for both military and commercial applications. By integrating the switches and filters we have reduced the overall package sizes by greater than 2:1 and reduced loss, leakage and cost by eliminating the interface connectors. These assemblies are available with amplifiers to improve Noise Figure and further reduce insertion loss.

High power switched assemblies that provide band rejection of unwanted frequencies. Examples are shown in our JTIDS catalog. Using high power PIN diode switches the notch filters can be switched in and out of the transmitter path on a pulse by pulse basis to protect TACAN and IFF receivers from JTIDS transmissions.

A new design effort at RS Microwave will allow us to integrate active low power circulators or isolators into assemblies at frequencies to 1 MHz! These non-ferrite devices, which are comprised of a ring of operational amplifiers, can improve impedance matching and provide 20 dB of isolation with no insertion loss. The devices operate from DC to 250 MHz and require only ± 5 VDC. They require less than 0.25 cu. inch in volume.

We are interested in solving your filter problems. We are also interested in integrating those filters into packages that will provide more performance for you. If you have a subsystem that operates around a filter - or you want to consider combining your filter into a subsystem to save size, weight, improve performance - give us a call OR EMAIL us!. We don't just build filters, we offer "global solutions" to your subsystem problems.