TMM4 Immersion Gold Pcb For RF And Microwave

Understanding Rogers TMM4: A Superior Material
The Rogers TMM4 is a thermoset microwave material that combines the best attributes of both ceramic and traditional PTFE laminates. Designed specifically for high plated-thru-hole reliability in strip-line and micro-strip applications, TMM4 is engineered from a ceramic, hydrocarbon-based polymer composite. This innovative material offers strong mechanical properties and exceptional chemical resistance without the specialized production techniques often required for ceramics and PTFE.

Key Features of Rogers TMM4 PCB
 

1. Dielectric Properties
The TMM4 PCB exhibits a dielectric constant (Dk) of 4.5 ± 0.045 at 10 GHz, which is essential for effective signal transmission. This characteristic allows for precise control over signal propagation, crucial in high-frequency applications. Additionally, the dielectric constant can reach up to 4.7 in the range of 8 GHz to 40 GHz, making it extremely versatile for various RF applications.

2. Low Dissipation Factor
With a dissipation factor (Df) of 0.002 at 10 GHz, the TMM4 PCB minimizes energy loss during signal transmission. This low Df ensures that more power is preserved in the signal, enhancing overall system efficiency.

3. Thermal Stability
The TMM4 PCB is capable of withstanding high temperatures, with a decomposition temperature (Td) of 425 °C. This thermal stability is vital for applications that may experience significant thermal stress. The material also features a thermal conductivity of 0.7 W/mK, promoting effective heat dissipation.

4. Coefficient of Thermal Expansion (CTE)
The CTE values for the TMM4 PCB are well-matched to copper, with 16 ppm/K in the X and Y axes and 21 ppm/K in the Z-axis. This matching helps prevent warping and delamination, ensuring reliable performance under varying temperature conditions.

Mechanical and Physical Properties
 

5. Mechanical Strength
The TMM4 PCB possesses strong mechanical properties, including a flexural strength of 15.91 kpsi and a flexural modulus of 1.76 Mpsi. These attributes provide durability and resistance to mechanical stress, essential for maintaining integrity in demanding environments.

6. Moisture Absorption
With a moisture absorption rate of 0.07% for 0.050" thickness and 0.18% for 0.125", the TMM4 PCB is highly resistant to environmental changes, which is critical for maintaining performance over time.

7. Chemical Compatibility
The TMM4 PCB is compatible with lead-free processes, making it suitable for modern manufacturing standards. Its resistance to process chemicals further reduces the risk of damage during fabrication.

PCB Stackup and Construction
Configuration: 2-layer rigid PCB
Copper Layer 1: 35 μm
Rogers TMM4 Core: 0.762 mm (30 mil)
Copper Layer 2: 35 μm

Board Dimensions: 192 mm x 115 mm (±0.15 mm)
Minimum Trace/Space: 5/7 mils
Minimum Hole Size: 0.5 mm
Finished Board Thickness: 0.8 mm
Finished Copper Weight: 1 oz (1.4 mils) for outer layers
Via Plating Thickness: 20 μm
Surface Finish: Immersion Gold
Silkscreen and Solder Mask:
Top Silkscreen: White
Bottom Silkscreen: None
Top Solder Mask: Green
Bottom Solder Mask: None

Quality Assurance: 100% electrical testing performed prior to shipment.

Typical Applications
The Rogers TMM4 PCB is versatile, making it suitable for a range of applications, including:

RF and microwave circuitry
Power amplifiers and combiners
Filters and couplers
Satellite communication systems
Global Positioning Systems (GPS) antennas
Patch antennas
Dielectric polarizers and lenses
Chip testers