RF-over-fiber developer PPM Systems has been recruited by the British Army for 90 custom filters for the British Army’s spectrum team based in Blandford Camp in Dorset County in southern England. The filters are part of a performance upgrade for the British Army’s Battlefield Tactical Communication and Information Systems (BATCIS) program, and advanced electronic system designed to provide secure tactical battlefield communications. The wide range of custom filters include narrowband cavity filters with bandpass and bandstop characteristics.
The compact cavity filters help isolate closely located transmitters and receivers operating within similar frequency ranges and reduce levels of intermodulation distortion (IMD) and out-of-band noise for receiver channels. Paul Cotterill, PPM Systems Business Development Manager, said: “This was a significant order for high-quality filters across 30 custom types and is a good example of PPM’s rapid design capability to supply these types of filters.” The firm offers a wide range of single-band and multiple-band cavity filters, such as the model CMIBF-433-1 bandpass filter (see figure) developed by Corry Micronics. The coaxial filter has a passband of 428 to 438 MHz with low passband insertion loss of less than 2 dB and VSWR of less than 1.50:1. It provides more than 30 dB rejection of signals from DC to 403 MHz and 463 to 500 MHz while handling input signal power levels to 10 W.