ROG Blog

The Rog Blog is contributed by John Coonrod and various other experts from Rogers Corporation, providing technical advice and information about RF/microwave materials.

Compare Materials in a Meaningful Way

Selecting a circuit board material for an application often comes down to a choice based on which has better specifications on the data sheet. Two different PCB materials from different suppliers might look identical in terms of key specifications, such as dielectric constant (Dk) and dissipation factor (Df), making a choice difficult. But how close are those two materials really? When can the data sheets look the same but the two materials be quite different?

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Hybrid Multilayer PCBs Help Keep Vehicles Safe

Advanced automotive electronics systems have relied on the reflections from on-board vehicular radar systems for some time. The vehicular radars are often fabricated on what are known as hybrid multilayer PCBs. These are PCBs formed of different kinds of circuit-board materials, matching the characteristics of the different materials to the needs of the different circuit functions, from DC through 77 GHz. Learn about designing with these new layers to realize better performing circuits at a lower cost.

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Making the Most of PCB Materials for 5G Microwave and mmWave Amps

5G may represent the latest and greatest in wireless technology, but it will be challenging to design and fabricate, starting with the circuit-board materials, because it will operate across many different frequencies, such as 6 GHz and below as well as at millimeter-wave frequencies (typically 30 GHz and above); it will also combine network access from terrestrial base stations and orbiting satellites. But by careful consideration of mechanical and electrical requirements, high-frequency circuit materials can be specified that enable the design and development of 5G PAs no matter the frequency.

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Which Dk Value is “Right” for my Computer Simulation?

Which Dk value is the one to use with a CAE circuit modeling program? Is the Design Dk the “right” Dk value when performing a circuit simulation, or might there be a case when one of the other Dk values for the same material might work better with a particular computer model? Find out in this blog post.

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Getting A Grip On The Glass Weave Effect

Millimeter-wave frequency bands hold valuable spectrum for what lies ahead: fifth-generation (5G) wireless communications and automotive collision-avoidance radar systems. For that to happen, low-loss laminates must be available for circuits operating from 60 through 77 GHz, without performance limitations placed by the glass weave effect at those high frequencies. Just what is the “glass weave” effect and what does it have to do with millimeter-wave circuits? It’s all about the wavelengths.

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Composite Materials Form Radiation-Free DGS Circuits

Filter and antenna designers have long appreciated the benefits of designing distributed high-frequency circuits using defected ground structure (DGS) layouts with different types of circuit materials. DGS shapes are often simple resonant u-shaped slots in the ground plane, intended to enhance the coupling of transmission lines or reduce harmonics. The design approach, which can be used with stripline and grounded coplanar waveguide (GCPW) circuits, is most often used with microstrip circuit designs.

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The Role of PCB Materials in Printed-Circuit Impedance

Printed circuits for high-speed and high-frequency applications rely on fine-featured transmission lines for signal transmission. Ideally, the loss through these transmission lines is minimal, and this requires an electrical impedance that is consistent and without interruptions, and with a value most appropriate for the types of signals to be transferred through the circuit. However, a number of factors can affect the impedance of a PCB, including the physical and electrical characteristics of the circuit and circuit material, but by reviewing and better understanding these variables, their effects can be minimized.

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Finish Makes a Difference in Final PCB Performance

The impact of final surface finish on circuit loss will depend not only on the type of surface finish but on the thickness of the substrate material and the type of transmission-line technology, such as microstrip or grounded coplanar waveguide (GCPW). This posting will describe some of the effects of various finishes.

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