Introduction
In RF, wideband has always been a dynamic and context-dependent term. Its definition evolves alongside advancements in technology and its applications. In electronic warfare (EW) systems, wideband capabilities are indispensable. They enable operations across an extensive range of frequencies and bandwidths (Figure 1) and facilitate quicker, more effective responses to modern threats.

Key EW applications such as searching, tracking, targeting, and communications rely heavily on wideband functionality to cover significant portions of the RF spectrum. As the complexity and scope of applications expand, managing a broader range of frequencies becomes increasingly critical. In this context, advancements in RF filter technologies are essential. Advanced filter types optimize wideband range management, supporting the DoD’s Electromagnetic Spectrum Superiority strategy (spectrum superiority) and the overall effectiveness of EW systems in conflict.
What is Wideband?
As a term, wideband lacks a fixed definition. Wideband has different definitions based on the specific application and part of the RF circuit under consideration. It can refer to the entire spectrum (Figure 2) or a broad range of frequencies within it. This variability underscores that wideband isn’t a one-size-fits-all concept but a dynamic parameter changing with future technologies.

In EW systems, wideband encompasses essential applications such as radar, signal intelligence (SIGNIT), and jamming. These functions enable forces to operate effectively over ever-expanding frequency ranges. For example, anti-access/area denial (A2/AD) systems often utilize wideband technologies to counter adversarial spectrum activities (Figure 2).
Building Wideband RF Systems for Electronic Warfare
EW has become a defining aspect of modern conflict, with wideband systems serving as the backbone for detecting, countering, and exploiting signals. As the physical RF spectrum expands, so do the operational demands placed on wideband systems. These capabilities are essential for both offensive and defensive operations (Figure 3), including:
- Detection Evasion
- Communication Jamming
- Channel Security

Wideband technology enables effective communication from ground-based radar systems to space-based surveillance and cyberspace operations. The EA-18G Growler, for instance, employs wideband systems to jam and disrupt enemy radar and communication signals to provide a tactical advantage in electronic warfare operations. Similarly, the EC-130H Compass Call utilizes wideband capabilities to intercept and exploit enemy communications.
Expanding the Boundaries of Wideband Range with RF Filter Solutions
Maintaining spectrum dominance is a top priority for modern EW. Advancements in RF filters are essential for addressing emerging challenges like countering stealthy, agile threats like frequency-agile radars, drones, and software (SDR) systems.
To overcome these challenges, EW systems must incorporate cutting-edge capabilities that enable:
- Resilient Communications: Ensuring robust, uninterrupted communication even under adversarial jamming attempts.
- Cognitive EW: Leveraging AI and machine learning (ML) to adapt dynamically to rapidly changing spectral conditions. AI-enhanced filters, for example, can optimize their performance in real time by adjusting parameters to accommodate fluctuating signal environments.
Balancing Signal Capture and System Efficiency
As engineers, capturing a wide range of signals while maintaining system efficiency is a significant challenge. Modern RF filter technology is advancing to meet the needs of mission-critical applications, particularly operating in lower frequency ranges from VHF to L bands. Different filter technologies excel in specific frequency ranges (Figure 4), each with unique strengths and challenges:
- Lumped Element Filters are compact and well-suited for lower-frequency applications. They can support very high percentage bandwidths. However, they face performance limitations at higher frequencies due to element parasitics.
- Ceramic Filters are well-suited for mid-range frequencies. They deliver high precision and stability in environments subject to temperature or vibration constraints. They are ideal for narrow bandwidths but are less scalable for extremely high frequencies.
- Cavity Filters offer a traditional approach to higher frequencies due to their low insertion loss and high selectivity. Depending on their manufacturing technology, their size may limit their use in compact systems.
- Planar Filters (like microstrips) offer a flexible approach to higher frequencies for their small, lightweight design. They can achieve relatively high percentage bandwidths.

The materials used alongside the design technique are a key factor in the performance of filter technologies—whether in terms of power handling, insertion loss, or temperature stability. To ensure optimal performance, some suppliers, like Knowles Precision Devices (KPD), develop and use their own ceramic materials across their ceramic, cavity, and planar filters.
Transforming Filter Design with RFADCs and RFSOCs
Emerging solutions, such as tunable filters and AI-enhanced adaptive filtering are further pushing the boundaries of what is achievable. Breakthrough technologies like RF Analog-to-Digital Converters (RFADCs) and RF System-on-Chip (RFSoC) are revolutionizing signal processing and ensure optimal performance in even the most challenging operational scenarios.
RFADCs: A Game-Changer in Wideband Processing
By enabling direct sampling of RF signals at exceptionally high speeds, RFADCs reduce system complexity by eliminating the need for traditional frequency conversion methods. They expand the bandwidth available for processing, allowing EW systems to monitor a broader range of frequencies in real time. For example, the Agilex™ 9 SoC FPGA from Intel is an RF-FPGA with 64Gsps ingest capabilities. It can handle vast amounts of data with unmatched speed and precision.
RFSoCs: Integration for Enhanced Efficiency
RFSoC technology is taking integration to the next level by combining multiple RF processing functions into a single chip. High-speed ADCs, digital signal processing (DSP), and RF signal management are all housed within one compact and efficient system.
By leveraging the capabilities of RFADCs and RFSoCs, engineers can develop EW systems that are more agile, efficient, and effective in contested spectral environments. These technologies are setting new standards for performance in wideband signal processing, ensuring spectrum dominance in the modern battlespace.
Discover Next Gen Wideband Solutions for EW at RFMW
The dynamic nature of wideband in EW demands innovative solutions and, as the spectrum continues to expand, flexibility in filter bandwidth and advanced signal processing technologies are essential for ensuring spectrum superiority.

Knowles Precision Devices (KPD) stands at the forefront of innovation in next-generation RF filter design. Available at RFMW, KPD offers a range of industry-leading solutions designed to meet the rigorous demands of modern EW systems. Their quasi-lumped filter solutions enable the combination of filter technologies to meet specific frequency, bandwidth, and size requirements (Figure 5).
Additionally, the B098QC5S Bandpass Filter is a popular choice among engineers for EW systems. Utilizing Knowles DLI brand’s low-loss, temperature-stable materials, the B098QC5S ensures consistent, reliable operation with minimal performance variation over a wide temperature range.
KPD’s line of fully shielded surface mount bandpass filters is ideally suited for EW applications. Without compromising on performance, these filters stand out as a cost-effective alternative for EW systems that require high precision and reliability. Their small form factor, with widths well below half a wavelength, ensures seamless integration into compact, high-density systems like beamforming arrays.
Part Number |
Fc (GHz) |
% Bandwidth |
2.105 |
5.0% |
|
3.25 |
30.8% |
|
3.81 |
10.0% |
|
4.5 |
48.9% |
|
8.42 |
10.0% |
|
10.0 |
40.0% |
|
42.4 |
7.1% |
Technical References:
- Defense Primer: Electronic Warfare IF11118
- EW: New Challenges, Technologies, and Requirements
- The sensor- and signal-processing challenges of electronic warfare
Recommended Reading
Technical Experts

Tim Daly is an RFMW Supplier Business Manager with over 30 years of experience in the RF & microwave industry. Tim has spent his career in product management and sales roles for well-known semiconductor companies, supporting some of the industries leaders in RF & microwave products.

Peter Matthews is Director of Technical Marketing at Knowles Precision Devices. Peter has over 25 years of experience in technology sales, marketing, and product management. In his current role, Peter assesses technology trends in existing and emerging markets to provide guidance on the impacts for Knowles, Knowles’ customers, and the industry overall.