The Role Of Filters In Expanding Bandwidth For Electronic Warfare Receivers

Electronic warfare (EW) systems are vital for controlling the electromagnetic spectrum in modern conflicts. EW encompasses three key sectors: electronic attack (EA), which disrupts or deceives enemy systems; electronic protection (EP), which defends against such attacks; and electronic support (ES), which gathers intelligence from electromagnetic signals. Designing systems to meet EW’s complex demands requires miniaturization, high performance, and real-time adaptability across a wide frequency range.

Engineers are integrating signal acquisition, processing, and generation into compact, multifunctional components. A major advancement in EW systems is the move toward digitizing signals earlier in the receive chain through software-defined radios (SDRs). Powered by evolving RF analog-to-digital converters (RF-ADCs), these systems can now sample broader portions of the spectrum directly at RF, reducing the need for intermediate frequency stages.

Despite the shift to digital, RF filters remain crucial. As SDRs become more susceptible to interference, filters are essential for functions like band selection and anti-aliasing. For instance, under-sampling in digital receivers—sampling signals above the Nyquist frequency—requires precise bandpass filtering to avoid noise aliasing and maintain dynamic range. Filters with steep slopes and wide bandwidths help isolate the desired frequency band while minimizing interference from neighboring spectral images.

Modern EW tuners use switched filter banks and wideband, high-rejection filters to manage bandwidth efficiently. These filters are critical enablers of advanced digital receiver architectures. As RF-ADC capabilities grow, the need for agile, high-performance filtering technologies becomes even more pronounced in supporting the evolving demands of electronic warfare.