Signal Clarity & High Radiolucency: Unlocking the Functional Core of Composite Sandwich Structures

In advanced engineering, composites have evolved beyond "lightweight and strong." From aerospace radomes and high-speed rail to medical CT systems and 5G/6G base stations, electromagnetic transparency and X-ray transmittance are now decisive performance metrics.

While carbon fiber or fiberglass skins form the outer shell, the true enabler lies in the core. This is where high-performance Polymethacrylimide (PMI) foam delivers unmatched value. With its intrinsically low dielectric constant and high radiolucency, PMI foam has become the gold standard for functional sandwich structures.

I. Low Dielectric Constant: Letting Signals Pass Without Interference

For radomes, 5G/6G antennas, and electronic housings, wave transparency is non-negotiable. If the core material has a high dielectric constant and loss tangent, electromagnetic waves suffer reflection, attenuation, and phase distortion — blinding radar systems or degrading signal quality.

PMI foam features a micro-closed-cell structure: tens of thousands of uniform cells filled with air. Since air has a dielectric constant close to 1.0, PMI foam achieves some of the lowest dielectric properties among all structural materials — typically 1.05–1.15, with minimal dielectric loss.

The manufacturing challenge:

During liquid resin infusion or autoclave curing, if the foam's surface cell size is too large, it absorbs excess resin like a sponge. Since typical resins have a dielectric constant of 3.0–4.0, any excess uptake significantly degrades the electrical performance of the entire sandwich structure.

XTylene® Fm Series by Xintan:

Hunan Xintan developed the XTylene® Fm Series PMI Foam, featuring micro-cell size constrained below 0.1 mm. This ultra-fine cell structure ensures exceptionally low surface resin absorption. After CNC precision machining, the surface remains mirror-smooth, forming a uniform, thin resin bond layer without unnecessary weight penalty. It delivers consistently low and stable dielectric properties — the premier choice for radomes and advanced wireless communication equipment.

II. High Radiolucency: Achieving "Absolute Clarity" in Medical Imaging

In medical radiology — CT bedboards, DR detector panels, mammography positioning devices — the critical metric for sandwich panels is X-ray transmittance. The lower the attenuation, the higher the image clarity.

If a core material absorbs too much X-ray radiation, two consequences follow:

• Image artifacts: Shadows or noise appear in scans, compromising clinical diagnosis.
• Increased radiation dose: The system must increase X-ray intensity to penetrate the attenuating material, raising patient exposure.

PMI foam consists inherently of low atomic number elements — Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N) — with no heavy metals. This molecular composition minimizes X-ray absorption, delivering excellent radiolucency.

XTylene® Tx Series by Xintan:

To meet the stringent demands of medical diagnostics and high-end aerospace components, Xintan offers the XTylene® Tx Series High-Performance PMI Foam. This series balances structural stability, high mechanical strength, low dielectric constants, and exceptional radiolucency. Rigorously validated through long-term partnerships with leading medical device and aerospace manufacturers, the Tx series excels in thermoforming, CNC machining, and high-temperature co-curing (up to 180°C autoclave cycles). It is the ultimate core for high-precision, artifact-free radiolucent structures.

III. Xintan New Material: Innovation-Driven, Globally Deployed

Founded in 2015 and headquartered in Changsha, Hunan Province, Hunan Xintan New Material Co., Ltd. is a National High-Tech Enterprise and a Technology-based SME. With a robust R&D foundation, the team has broken through multiple technical bottlenecks in high-performance PMI foam.

The XTylene® PMI foam series and custom machined parts now match international advanced technical standards, offering a reliable, high-performance alternative to legacy monopolies. Xintan products serve leading manufacturers across aerospace, radomes, medical devices, UAVs, and RVs, with exports to Europe, the Americas, Japan, and South Korea.

Our product lines include:

• Aa Series— Wave-Absorbing
• Fm Series— Fine-Cell, Low Dielectric
• TH/Tx Series— High-Strength & High-Temperature
• Y Series— Cost-Effective
• Zs Series— Flame-Retardant

Beyond standard PMI foam blocks, we operate a state-of-the-art CNC precision machining facility supporting Zero MOQ. Whatever the complexity of your 3D custom core geometry, we machine it to specification — ready for immediate layup.

Let's Talk Engineering.

Are you a composite structural engineer, a radome designer, an R&D lead for medical devices, or a supply chain specialist?

Need precise dielectric constants, loss tangents, or mechanical baseline data for your FEA?

Looking to request a test sample for your next prototype?

Leave a comment or send a direct message. Our technical team will respond with your custom core solution.

Xintan New Material — Empowering a Lightweight Future with Core Innovation.