Feature: Thermal management


In applications where heat conduction is critical, such as in the vacuum of space, engineers must consider thermal conductivity of available substrates or use filled vias as an alternative thermal path within the design


Plated-through vias are oſten


recommended for low-power applications, with filled vias being ideal for high power because they help transfer heat away from the substrate. Filled vias also offer the lowest RF inductance.


Critical applications In a LEO satellite, thin-film substrates oſten form the foundation of transceiver modules, frequency converters, phased array control circuits and sensor readout electronics. In LEO, substrates face thermal cycling


every 90 minutes as the spacecraſt moves in and out of sunlight. Tese satellites are also exposed to vacuum and radiation. Such influences cause dimensional changes, dielectric property shiſts and microcracking in poorly matched materials. Reliability is therefore critical because satellites can’t be repaired once in orbit, and any electrical driſt can have serious consequences. For drones, the ability to integrate


precision RF and high-speed digital components in a small footprint translates directly into more capable payloads, without increasing size or mass. In surveillance drones, thin-film substrates are used in the microwave circuits of synthetic aperture radar or high-resolution imaging payloads. In strike drones, they might be part of encrypted communication modules or electronic countermeasure systems. Even in smaller tactical drones, they may be embedded in compact GPS receivers or advanced telemetry systems to ensure reliable navigation and data links. Equally, military ground-based,


shipborne and airborne radars all rely on consistent RF performance, since small electrical variations can cause significant


degradation in system performance. In phased-array radar modules, thin-film substrates support the radar’s ability to achieve long-range detection, high resolution and resistance to jamming. In active electronically scanned arrays (AESA), each transmit/receive module needs to handle high-frequency RF signals with exact phase and amplitude control. Te fine line tolerances of thin film patterned substrates (Figure 3) ensure that microstrip or co-planar lines have predictable impedance and minimal loss, so beam steering and radar resolution remain consistent across hundreds or even thousands of modules. In satellite and space communication


payloads, thin-film patterned substrates are critical because they combine high- frequency capability with survivability in vacuum and radiation environments. Aluminium nitride-based thin-film boards, for example, can dissipate heat from high-power amplifiers efficiently, while maintaining structural stability through the extreme thermal cycles of orbit, oſten from -150°C in shadow to +150°C in sunlight. Space-qualified versions of these substrates must follow NASA’s EEE- INST-002 or the European ECSS-Q-ST-60 guidelines, which cover material choices, metallisation thickness, adhesion strength and environmental testing. Avionics and flight control electronics


also make heavy use of thin-film patterned substrates. Precision navigation systems, sensor processing units and communications modules oſten operate in environments with constant vibration, rapid altitude changes and wide temperature swings. Te controlled thermal expansion of ceramics like alumina and aluminium nitride reduces


32 September 2026 www.electronicsworld.co.uk


mechanical stress on the circuitry, which helps prevent cracking or delamination over time. Tis is especially important for components mounted near engines or in other high-heat zones. Tin-film substrates also play a critical


role in electronic warfare (EW) and jamming systems. A substrate that shiſts in impedance or resonant frequency due to thermal expansion, mechanical stress, or moisture ingress could instantly reduce jamming effectiveness or allow an enemy radar to regain a track. By minimising loss, preserving phase


and amplitude accuracy, and resisting environmental driſt, they ensure that a jammer can place energy exactly where it’s needed in the spectrum whilst keeping friendly systems free from self-interference. Tis combination of precision and durability is what enables EW platforms to operate effectively in the crowded, contested electromagnetic battlespace. Functionally, thin-film substrates in


radios and SATCOM systems enable compact, lightweight and precisely- tuned RF modules that can maintain link quality, frequency stability and filtering performance even under extreme environmental conditions. By minimising insertion loss, preserving


phase accuracy and allowing for complex multi-function integration in a small footprint, they ensure that communication links remain clear, secure and reliable in mission-critical operations.


Ensuring precision and long-term stability Because they support extremely fine conductor geometries with tight tolerances, thin-film substrates enable the high levels of miniaturisation required in antenna feed networks, RF amplifiers, radar front-ends, GPS modules, high-frequency filters and phased-array control electronics. For engineers working with LEO


satellites, drones, radar systems and advanced communications equipment, these substrates provide the precision and long-term stability essential for RF, microwave and high-speed digital circuits to perform reliably throughout the entire mission life.


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