Dielectric constant (relative permittivity) is one of the most important electrical properties when selecting substrates for RF devices, microwave circuits, antennas, semiconductor fabrication, MEMS, photonics, and optoelectronics. Engineers and researchers compare the dielectric constant and dielectric loss of materials such as silicon, sapphire, fused silica, quartz, gallium arsenide, lithium niobate, germanium, and silicon carbide to optimize signal performance, reduce power loss, and improve device reliability. This guide explains dielectric properties and provides real-world examples of substrate materials used in advanced electronic and communications applications.
Engineers developing base station antennas, RF devices, microwave circuits, and wireless communication systems often need substrate materials with a controlled dielectric constant, high permittivity, and low dielectric loss.
Customer Request:
An electrical engineer requested high-permittivity blocks for new base station antenna designs. The requested dimensions were approximately 4 cm x 4 cm x 4 cm, with an initial quantity of 36 pieces and possible future production quantities.
The critical requirements were a high dielectric constant around 35 to 50 and the lowest dielectric loss possible.
UniversityWafer, Inc. helps researchers and engineers source dielectric substrate materials for antennas, RF components, microwave devices, capacitors, insulators, and semiconductor applications.
Reference #252428 for specs and pricing.
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Dielectric loss is the electrical energy that is converted into heat when an insulating material is exposed to an alternating electric field. For RF substrates, antennas, capacitors, microwave circuits, and high-speed electronics, dielectric loss is an important performance factor.
Low dielectric loss materials help reduce signal attenuation, heat generation, and power loss. This is especially important in high-frequency applications where even small material losses can affect antenna efficiency, filter performance, and signal integrity.
Dielectric loss is often described using loss tangent, also written as tan δ. A lower loss tangent is usually preferred for RF, microwave, antenna, resonator, and high-frequency substrate applications.
Knowing the dielectric loss of a substrate helps engineers choose the right material for reliable electrical and electronic performance.
A customer requested the dielectric constant for a silicon carbide substrate with 4H single crystal structure, nitrogen doping, epi-ready polish, and 150mm diameter.
Example SiC Substrate:
Silicon Carbide Dielectric Constant: approximately 9.66.
Reference #279361 for specs and pricing.
For low-loss RF, optical, MEMS, and insulating applications, researchers often request glass wafers or fused silica wafers with a low dielectric constant and thin wafer thickness.
Postdoctoral Research Request:
A researcher requested a glass wafer material with the lowest available dielectric constant and a thickness below 0.150 mm. Fused silica was recommended because of its low dielectric constant, optical clarity, and useful dielectric properties for electronic and RF designs.
Reference #143277 for specs and pricing.
The dielectric constant, also called relative permittivity, describes how a material responds to an electric field. For wafers and substrates, this property is important when choosing materials for RF devices, microwave circuits, antennas, capacitors, MEMS, optics, and semiconductor applications.
A higher dielectric constant means the material stores more electrical energy in an electric field. A lower dielectric constant is often preferred for high-frequency and low-loss applications where signal speed, impedance control, and low heat generation are important.
Below are approximate dielectric constant values for common substrate materials used in research, RF engineering, semiconductor processing, and optical applications.
| Material | Approx. Dielectric Constant | Common Applications |
|---|---|---|
| Silicon (Si) | 11.7 | Semiconductors, MEMS, sensors, IC fabrication |
| Gallium Arsenide (GaAs) | 12.9 | RF devices, microwave electronics, photonics |
| Fused Silica | 3.8 | Low-loss substrates, optics, antennas, insulating wafers |
| Single Crystal Quartz | 4.5–4.7 | Oscillators, optics, RF components, waveplates |
| Lithium Niobate (LiNbO₃) | 28–44 | Optical modulators, waveguides, piezoelectric devices |
| Germanium (Ge) | 16 | Infrared optics, detectors, semiconductor devices |
| Sapphire (Al₂O₃) | 9–11 | RF substrates, GaN growth, optics, high-temperature devices |
| Silicon Carbide (SiC) | 9.66 | Power electronics, RF devices, high-temperature applications |
| Borosilicate Glass | 4.0–5.0 | Glass wafers, optics, MEMS, insulating substrates |
Choosing the correct dielectric constant helps engineers control capacitance, impedance, signal speed, antenna size, and electric field distribution. This is especially important for RF substrates, microstrip antennas, microwave circuits, semiconductor devices, and high-frequency electronics.
Dielectric loss describes how much electrical energy is converted into heat when a material is exposed to an alternating electric field. In RF and microwave applications, low dielectric loss is just as important as dielectric constant because excessive loss can reduce signal strength and increase heating.
The loss tangent, often written as tan δ, is used to compare how efficiently a dielectric material performs at a specific frequency. Materials with a low loss tangent are preferred for antennas, resonators, microwave circuits, filters, and high-speed electronics.
Fused silica wafers are often selected for S-band antennas, CubeSat components, solar cell cover glass, and low-loss RF applications because they combine a low dielectric constant with excellent optical clarity and thermal stability.
Researcher Application Example:
A postdoctoral student requested fused silica glass substrates for S-band microstrip antennas used with CubeSat solar cell cover glass. The researcher needed dielectric constant and loss tangent information to evaluate fused silica for a narrowband antenna design.
Sapphire wafers are useful for microwave passive devices because sapphire has excellent hardness, thermal stability, chemical resistance, and low microwave loss. Sapphire is also used for GaN epitaxy, RF devices, optical windows, sensors, and high-temperature electronics.
For sapphire, dielectric constant can depend on crystal orientation. A typical value is approximately 11.5 parallel to the C-axis and 9.3 perpendicular to the C-axis.
UniversityWafer, Inc. Quoted Example:
C-plane sapphire wafers with double-side polish, epi-polished front surface, fine-polished back surface, low TTV, and low surface roughness for microwave passive device research.
Reference #211126 for specs and pricing.
Dielectric breakdown occurs when an insulating material becomes electrically conductive because the electric field is too strong. Once breakdown occurs, the material may no longer work as a reliable insulator.
Dielectric breakdown is important when selecting substrates for capacitors, insulators, RF devices, antennas, high-voltage electronics, and semiconductor components. Materials with high breakdown strength help improve reliability and reduce the risk of electrical failure.
UniversityWafer, Inc. supplies semiconductor, glass, sapphire, quartz, fused silica, lithium niobate, gallium arsenide, silicon carbide, and custom substrate materials for research and production. Send us your required dielectric constant, loss tangent, thickness, diameter, orientation, polish, and quantity for a fast quote.