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

How to Transition from Designing for Microwave Frequencies to Millimeter-Wave Frequencies

Higher frequency PCBs require a thoughtful choice of circuit materials well suited for millimeter-wave frequencies and circuit fabrication processes that support those higher frequencies. Part 1 of this blog will explore circuit material characteristics that make them best suited for millimeter-wave frequencies. Part 2 will examine high frequency structures and the fabrication processes that can help them do best at millimeter-wave frequencies.


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Boards

Bonding Materials Minimize Loss in Multilayer Millimeter-Wave PCBs

As the demand grows for circuits serving available frequency spectrum in the mmWave range, circuit designers are meeting those demands using newer low loss circuit materials or hybrid circuits composed of multiple layers of dissimilar circuit materials, such as very low loss circuit materials for higher-speed, higher-frequency circuits and more cost effective circuit materials such as FR-4 for functions such as ground planes, power planes, and control lines not requiring such low loss circuit material.


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Thoughtful Material Choices Can Help Shrink RF Circuits

Smaller is often wiser in this age of electronic mobility and portability, and the choice of circuit material when starting a design has much to do with attempts to create smaller RF and microwave circuits. Circuit materials with higher dielectric constant (Dk) typically yield circuits with smaller features and dimensions for a given frequency range. But the higher Dk values can also result in increased insertion loss and other performance tradeoffs. The Dk value of a circuit material will also impact such circuit parameters as radiation loss, dispersion, and coupling.


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ROG 10 Years

Ten Years of Blogging on Microwave Journal’s Website

10 Years of the ROG Blog and It May Just Be the Start

Ten years ago, when we started the ROG Blog with the help of Microwave Journal’s dedicated editorial staff, it might have seemed impossible to keep a regularly scheduled blog on circuit materials going for even a few years, let alone for 10, without undue repetition. But the continued interest in the ROG Blog from our readers—thank you, folks—and the ever-improving quality of the circuit materials that we are writing about has “fueled the fire” and given us much to write about.


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Make Practical Use of GCPW at mmWaves

Successful application of GCPW technology involves understanding how the performance levels from fabricated PCBs can differ from the near-ideal performance levels predicted for GCPW circuit designs by commercial computer-aided engineering (CAE) software tools. A few factors can lead to differences between what the software predicts and what is achieved by a GCPW circuit, especially for mmWave circuit designs at high volumes.


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Extending Stripline PCBs to Millimeter-Wave Frequencies

Designing and fabricating a printed circuit board (PCB) at millimeter-wave frequencies starts with the circuit material, although the choice of transmission-line technology can play quite a part in how much performance can be delivered at those high frequencies. Learn about extending stripline PCBs to mmWave frequencies


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Dk Measurements are Affected by Various Test Methods

Mobile wireless communications systems are moving to their fifth generation (5G) and with them, the world is moving to millimeter-wave (mmWave) frequencies. For many circuit designers, this means taking a hard look at their choice of printed circuit board (PCB) material to understand how well it will perform in 5G circuits and systems at mmWave frequencies. It means counting on that circuit material for a value of permittivity or dielectric constant (Dk) that will be the foundation of many new designs, counting on a circuit material supplier’s Dk measurements. But how reliable are those Dk measurements?


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CoonrodsCorner

Why TCDk Circuit Performance Testing is Critical, in Order to Understand Environmental Influences

TCDk is a property which all circuit materials possess and it is how much the Dk of the material will change, with a change in temperature. The default test method for determining TCDk is typically done as a raw-material test and this video gives an outline of how to perform TCDk testing in circuit form. The circuit form testing for TCDk is considered a real-world test as opposed to the raw-material test method, which is typically intended for material characterization. Watch this video from John Coonrod covering this topic.


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