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.

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.

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.

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.

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.

Much of the buzz on the show floor at the 2017 IMS in Honolulu was about millimeter-wave devices and circuits. At one time, frequencies above 30 GHz were considered “exotic” and only for military or scientific applications. But times have changed, and available spectrum is scarce.

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.

Woven glass is incorporated into printed-circuit-board (PCB) materials to provide structural strength. It aids the mechanical stability of a laminate, but what does it do to its electrical behavior? One of the classic concerns regarding woven glass reinforced laminate PCBs is that the “glass weave effect” can have negative impact on the electrical performance of high-speed or high-frequency circuits fabricated on these laminates. In this blog, we examine some of the factors affecting the glass weave effect phenomenon.

Circuit materials are evaluated by a number of different parameters, including dielectric constant (Dk) and dissipation factor (Df). Those two parameters also have temperature-based variants that provide insight into the expected behavior of a circuit material with changes in temperature, notably the thermal coefficient of dielectric constant (TCDk) and the thermal coefficient of dissipation factor (TCDf).