Rogers RT Duroid 5880 PCB
Rayming PCB & Assembly
Printed Circuit Board Manufacturing and PCB Assembly Services
Introduction
Rogers RT Duroid 5880 is a high frequency laminate material made by Rogers Corporation specifically for RF/microwave circuit board applications. It is one of the most popular PTFE composite substrates used for making high frequency analog and digital circuits operating up to mmWave frequencies. The 'RT Duroid' brand name comes from the fact that this material integrates Roger's proprietary PTFE composite dielectric with a woven glass reinforcement making it extremely rugged and durable.
In this article we will take a deep dive into understanding the salient features, properties, performance and applications of this versatile microwave substrate.
Overview of Rogers RT Duroid 5880 Substrate
Rogers RT Duroid 5880 is a ceramic-filled PTFE composite material clad with rolled copper foil on both sides. The dielectric constant of RT Duroid 5880 is 2.20 at 10 GHz with a tolerance of ±0.02. The low dielectric constant and tight tolerance makes it suitable for a wide array of high frequency applications.
Some of the key features and benefits of RT Duroid 5880 are:
Typical Properties of Rogers RT Duroid 5880
Rogers RT Duroid 5880 substrate is offered in different dielectric core thicknesses ranging from 0.008" (0.2 mm) to 0.250" (6.35 mm). It comes clad with rolled copper foil on both sides with standard 1 oz (35 μm) foil. Thicker 2 oz and 3 oz copper foils are also available. The typical properties of RT Duroid 5880 are summarized below:
PropertyValueDielectric Constant (10 GHz)2.20 ± 0.02Loss Tangent (10 GHz)0.0009Dielectric Strength>40 kV/mmVolume Resistivity>1017 ohm-cmSurface Resistivity>1015 ohms/squareWater Absorption<0.02%Coefficient of Thermal Expansion17 ppm/°CThermal Conductivity0.71 W/m/KGlass Transition Temperature>280 °C
Frequency Stability of Electrical Properties
One of the major benefits of Rogers RT Duroid 5880 substrate is that its dielectric constant and loss tangent remain very stable over a wide frequency range. This stability of electrical properties allows consistent circuit performance across different frequency bands.
The plot below shows the dielectric constant and loss tangent variation with frequency for RT Duroid 5880:
FrequencyRelative PermittivityLoss Tangent1 MHz2.220.000451 GHz2.220.000910 GHz2.200.000920 GHz2.190.000940 GHz2.180.0009
As seen above, the permittivity only changes from 2.22 to 2.18 over 1 MHz to 40 GHz, while the loss tangent remains fixed at 0.0009. This makes the material suitable for multi-band and wideband RF circuit designs.
High Frequency Applications
Thanks to its unique combination of electrical and mechanical properties, Rogers RT Duroid 5880 substrate is used to fabricate high frequency analog and digital circuits operating from L-band to mmWave frequencies.
Some of the common applications of this substrate include:
The low loss and tight dielectric tolerance allows building high performance passive circuits like filters and couplers on RT Duroid 5880. The stable properties versus temperature minimize drift in filters or VCOs. The ruggedness of the material makes it suitable for airborne radars and other defense systems. The woven glass does not require bonding plies for most applications.
With the excellent high frequency performance and ease of fabrication, RT Duroid 5880 has become the substrate of choice for numerous commercial wireless as well as hi-rel defense programs.
CIRCUIT Microstrip Line Design on RT Duroid 5880
Rogers RT Duroid 5880 is an excellent substrate for designing microstrip transmission lines. The low dielectric constant translates into wider line widths and lower losses.
For instance, a 50 Ohm microstrip line on a 20 mil thick RT Duroid 5880 substrate would have the following dimensions:
This translates into a very practical linewidth not prone to fabrication tolerances. Furthermore, a 50 Ohm line on RT Duroid 5880 provides lower loss compared to standard FR4 material due to the lower loss tangent. This allows realization of longer transmission lines with smaller loss.
The table below provides the impedance and physical dimensions for some commonly used microstrip lines on 20 mil RT Duroid 5880 material:
领英推荐
Line Impedance (Ohms)Line Width (mils)2524.13518.15011.8756.81004.2
Rogers provides free online tools like RT/Duroid 5880 Transmission Line Calculator which can be used to determine the line dimensions and loss for this substrate.
Fabrication Methods
The ruggedness and dimensional stability inherent in Rogers RT Duroid 5880 material allows use of a variety of circuit board fabrication techniques. Some of the popular structuring methods used are:
Chemical Etching
Most common way of patterning copper cladding into circuit traces. Provides excellent copper thickness control and resolution down to 3-5 mil traces.
Laser Cutting
A quick way to make prototypes by directly cutting out the circuit patterns with a laser. Allows fast design iterations.
CNC Machining
For quickly creating 3D structures like waveguides and cavities by mechanically milling. Provides excellent dimensional accuracy.
Automated Assembly
Suitable for automated assembly and soldering of surface mount components. The low Z-axis CTE minimizes solder joint stresses.
Rogers RT Duroid 5880 material is also compatible with advanced circuit board fabrication techniques like:
This allows creation of complex multilayer boards, HDI boards, via fences and other structures needed for sophisticated microwave modules and packages.
Summary
In summary, Rogers RT Duroid 5880 is a premier microwave substrate designed for performance sensitive high frequency applications. The key benefits of using RT Duroid 5880 are:
With its unique combination of electrical performance, mechanical reliability and ease of fabrication, RT Duroid 5880 has become the substrate of choice for high frequency analog and digital circuits across commercial and defense applications.
Frequently Asked Questions
Here are some common FAQs about Rogers RT Duroid 5880 laminates:
Q1. What is the dielectric constant range available for RT Duroid 5880?
A1. The standard dielectric constant is 2.20. However, Rogers can supply modified versions ranging from 2.17 to 2.33 on special request to meet specific impedance needs.
Q2. What are the standard copper cladding options for RT Duroid 5880?
A2. It is normally clad with 1 oz (35 μm) rolled copper on both sides. Thicker 2 oz (70 μm) and 3 oz (105 μm) foils are available for high power handling. 1/2 oz (17 μm) foils can also be supplied.
Q3. Can RT Duroid 5880 be used for lead-free soldering?
A3. Yes, RT Duroid 5880 is fully compatible with lead-free soldering processes, with a glass transition temperature exceeding 280°C. The low Z-axis CTE also minimizes solder joint stresses.
Q4. What is the shelf life of RT Duroid 5880 material?
A4. The shelf life is 1 year from the date of shipment when stored in proper conditions. Rogers also offers its RoHS-compliant TR/DUROID 5880 laminates with a 2-year shelf life.
Q5. Does RT Duroid 5880 require bonding ply layers?
A5. No bonding plies are required for most applications thanks to the woven glass reinforcement. Bonding films may only be required for specialized multilayer boards with very thick dielectrics.