What is the frequency of Rogers PCB?

Frequency Range of Common Rogers PCB Materials

Some of the most widely used Rogers high frequency PCB substrate materials include:

Material	Frequency Range	Dielectric constant (Dk) @ 10 GHz	Dissipation Factor (Df) @ 10 GHz
RO3003	Up to 77 GHz	3.00 ± 0.04	0.0010
RO4350B	Up to 40 GHz	3.48 ± 0.05	0.0037
RO4360G2	30-80 GHz	6.15 ± 0.15	0.0038
RT/duroid 5880	10-77 GHz	2.20 ± 0.02	0.0009
RT/duroid 6002	8-40 GHz	2.94 ± 0.04	0.0012

These Rogers materials support RF, microwave, and millimeter wave PCB applications like:

• 5G infrastructure
• Automotive radar
• ADAS
• Aerospace & defense radar and communications
• SATCOM
• Point-to-point wireless
• Test & measurement equipment

The low dielectric loss and stable Dk over frequency allow Rogers PCBs to maintain signal integrity for high-speed digital and high frequency analog circuits. The thermal conductivity also enables reliable power handling.

Selecting Rogers PCB materials by Frequency

Here are some general guidelines for choosing Rogers laminates based on operating frequency:

1-10 GHz

For L-band, S-band, and C-band frequencies from 1-10 GHz, Rogers materials like RO4000 series (RO4350B, RO4360G2) and RT/duroid 6002 provide a good mix of performance and cost for medium power applications.

Key considerations in this range:
– Dk tolerance
– Insertion loss
– Thermal conductivity for RF power amps

10-40 GHz

X-band, Ku-band, K-band, and Ka-band applications from 10-40 GHz benefit from Rogers laminates with lower dielectric constant and dissipation factor like RT/duroid 5880 and RO3003.

Select materials for:
– Phase stability over temperature
– Passive intermodulation (PIM) performance
– Dimensional stability for thinner laminates

40-100+ GHz

For millimeter wave frequencies in V-band, E-band, and W-band, extremely low-loss materials like RO4360G2 and RT/duroid 5880 are required. Precise control of Dk and Df are critical.

At these frequencies:
– Surface Roughness increases conductor loss
– Thinner laminates (<5 mil) needed for line widths
– Dimensional stability is critical
– Thermal management is a challenge

Impact of Laminate Properties on High Frequency PCBs

The key properties that affect a PCB laminate’s frequency range include:

Dielectric Constant (Dk)

Dk represents the ability of a material to store electric field energy. In general, a lower and more tightly controlled Dk is desirable for higher frequencies to minimize dispersion and losses. Rogers high frequency PCBs offer Dk from 2.2 to around 6.5.

Dissipation Factor (Df)

Also known as dielectric loss tangent or tan δ, Df quantifies a laminate’s tendency to absorb energy from the propagating signal. Lower Df is always better, especially for millimeter wave designs. Rogers PCBs provide some of the lowest Df available, down to 0.0009 for RT/duroid 5880.

Thickness

A thinner dielectric layer reduces capacitance between conductors, which is important for controlled impedance at higher frequencies. Rogers offers PCB laminates down to 2 mil (0.002″) thickness for mmWave applications.

Dk and Df Consistency

Consistent Dk and Df across the PCB are essential to maintain impedance control and avoid signal integrity issues. Rogers tightly controls material properties to minimize variances.

Thermal Conductivity

Higher thermal conductivity allows the PCB to dissipate heat more effectively, which improves reliability for high-power RF applications. Rogers PCBs offer thermal conductivity up to 1.44 W/m•K for RO4360G2.

By selecting the appropriate Rogers material based on frequency and key properties, designers can optimize high frequency PCB performance and manufacturability. Rogers provides detailed data sheets and design support to assist.

High Frequency PCB Design Considerations

In addition to the laminate material, several PCB design factors also impact high frequency performance:

Transmission Line Geometry

Microstrip, stripline, and grounded coplanar waveguide (GCPW) are common PCB transmission line types for RF and microwave frequencies. The geometry and dimensions determine the characteristic impedance and losses.

Copper Surface Roughness

Rougher copper surfaces increase conductor losses due to the skin effect at high frequencies. Rogers offers VLP (very low profile) and IMP (improved surface profile) copper foils to minimize surface roughness.

Artwork Precision

The line width and spacing tolerances become more critical at higher frequencies to maintain impedance control. Rogers PCBs have tightly controlled Dk and thickness to enable precise artwork.

Via Design

Through-hole vias can act as stubs and resonate at high frequencies, causing signal degradation. Blind and buried microvias are preferred for mmWave PCBs to minimize discontinuities. The laminate material must be compatible with laser microvia formation.

Shielding and Isolation

Effective shielding between PCB layers and along the edges is important to prevent crosstalk and interference at high frequencies. Rogers offers PCB materials with conductive claddings for enhanced isolation.

By optimizing the PCB layout and stack-up based on the Rogers material properties and application frequency, designers can achieve reliable high-frequency performance.

Advantages of Rogers PCBs for High Frequencies

Compared to standard FR-4 glass epoxy PCBs, Rogers high frequency laminates offer several benefits:

1. Lower dielectric loss for reduced signal attenuation
2. Tighter Dk control for consistent impedance
3. Thinner laminates for finer lines and spaces
4. Higher thermal conductivity for improved heat dissipation
5. Better dimensional stability over temperature
6. Lower moisture absorption for improved reliability
7. Compatible with advanced PCB fabrication processes

These advantages make Rogers PCBs an ideal choice for demanding high frequency applications where signal integrity, power handling, and reliability are critical. From 5G infrastructure to aerospace and defense systems, Rogers materials enable cutting-edge RF and microwave technologies.

FAQ

What frequencies do Rogers PCBs support?

Rogers offers PCB materials engineered for frequencies from RF to millimeter wave, covering L-band through W-band and beyond (1 GHz to over 100 GHz). The specific frequency range depends on the Rogers material grade selected.

What Rogers PCB material is best for 5G?

5G covers a wide range of frequencies, from sub-6 GHz to mmWave. Rogers materials like RO4000 series, CLTE series, and RT/duroid 5880 are widely used for 5G infrastructure. RO4360G2 and RO3003 are well-suited for mmWave 5G applications.

How do I select the right Rogers material for my frequency?

Key considerations for Rogers material selection include:
– Dielectric constant (Dk) and dissipation factor (Df) at the operating frequency
– Power handling and heat dissipation requirements
– Thickness availability and dimensional stability needs
– Cost and availability targets

Rogers provides detailed data sheets and an online Material Selection Guide to assist. Working with an experienced PCB fabricator is also recommended.

Can I use Rogers PCBs for high-speed digital applications?

Yes, Rogers materials are commonly used for high-speed digital applications up to 56 Gbps and beyond. The low loss tangent and stable Dk properties help maintain signal integrity for fast rise times and tight impedance control. Many Rogers PCBs are certified for high-speed standards like IEEE and OIF.

Are Rogers PCBs more expensive than FR-4?

In general, Rogers high frequency laminates are more expensive than standard FR-4 due to the specialized materials, tighter tolerances, and advanced manufacturing processes required. However, the performance advantages often justify the added cost for demanding applications. Rogers also offers lower-cost materials like RO4000 series that are more affordable than ceramic-filled PTFE laminates.

Conclusion

Rogers PCB materials are engineered to provide reliable performance across a wide range of high frequencies, from RF to millimeter wave. By selecting the appropriate Rogers material based on key properties like dielectric constant, dissipation factor, and thickness, designers can optimize signal integrity and power handling for applications such as 5G, automotive radar, aerospace and defense systems, and high-speed digital communications.

While Rogers PCBs are generally more expensive than standard FR-4, the performance advantages make them an essential choice for demanding high frequency designs. As data rates continue to increase and wireless systems move to higher frequencies, Rogers materials will play a critical role in enabling next-generation technologies.