Today, we will be discussing Rogers' AD255C antenna grade laminate and the printed circuit boards built using this antenna material.

AD255C copper clad laminates combine a fluoropolymer resin system with selected ceramic materials and fiberglass reinforcement, offering exceptional thermal properties. They exhibit lower loss, lower thermal expansion, and lower passive intermodulation (PIM). These laminates provide stability over a wide range of frequencies and temperatures, making them ideal for various microwave and radio frequency applications in telecommunications infrastructure.

The inclusion of micro-dispersed ceramics improves the thermal stability of AD255C by reducing its CTE values and enhancing phase stability at different temperatures.

Now, let's dive into the data sheet to explore the properties of AD255C.

AD255C Typical Properties

One of the most impressive features of AD255C is its PIM rating of -159/-163 dBc. Using reverse treated ED copper foil, typical PIM values are -159 dBc at a thickness of 30 mil and -163 dBc at a thickness of 60 mil. These values were obtained through extensive PIM testing at Rogers, conducted at 1900 MHz using a swept tone, reflected method on a 50Ω microstrip test vehicle.

AD255C has a dielectric constant of 2.55 (process) and 2.60 (design), enabling excellent signal transmission at high frequencies.

The material also boasts an extremely low dissipation factor of 0.0013 and high electrical strength of 911 V/mil, contributing to its outstanding electrical performance.

AD255C exhibits a thermal coefficient of dielectric constant of -110 ppm/ºC at a frequency of 10 GHz over the temperature range of 0°C to 100°C, as tested according to IPC TM-650. This negative coefficient indicates that the dielectric constant decreases with increasing temperature.

Volume resistivity and surface resistivity at C-96/35/90 are 7.4 x 10^8 Mohm-cm and 3.6 x 10^7 Mohm, respectively, as per IPC TM-650 2.5.17.1.

Dielectric breakdown in both the X and Y directions exceeds 40 kV, measured by D-48/50, IPC TM-650 2.5.6.

In terms of thermal performance, AD255C has a decomposition temperature exceeding 500 ˚C and a thermal conductivity of 0.35 W/mK in the z direction.

The material also exhibits a low coefficient of thermal expansion of 34 ppm/˚C (x-direction), 26 ppm/˚C (y-direction), and 196 ppm/˚C (z-direction) over the temperature range of -55˚C to 288˚C.

AD255C has a delamination time of over 60 minutes at 288˚C, making it an ideal material for high-temperature applications.

Regarding mechanical properties, AD255C demonstrates a copper peel strength of 2.4 N/mm after thermal stress, allowing it to withstand challenging environments.

The material also exhibits excellent flexural strength of 8.8/6.4 MPa in the machine direction and cross direction.

Tensile strength in the machine direction is 8.1 MPa, while in the cross-machine direction, it is 6.6 MPa at 23°C and 50% relative humidity, following the ASTM D3039/D3039-14 standard.

Flex modulus in the machine direction is 930 MPa, and in the cross-machine direction, it is 818 MPa at 25°C, as per IPC-TM-650 Test Method 2.4.4.

The dimensional stability is 0.03 and 0.07 mils/inch in the cross direction and cross-machine direction, respectively, after etching and baking.

Additionally, AD255C has a flammability rating of V-0 grade, a low moisture absorption rate of 0.03%, a density of 2.28 g/cm3, and a specific heat capacity of 0.813 J/g°K.

PCB Capability (AD255C)

We offer a diverse range of PCB manufacturing capabilities to accommodate various project specifications.

These options include layer count variations such as double-sided PCBs, multi-layer PCBs, and hybrid-designed boards.

Copper weight options can be 1oz (35µm) and 2oz (70µm), and dielectric thickness options include 20mil (0.508mm), 30mil (0.762mm), 40mil (1.016mm), 60mil (1.524mm), and 125mil (3.175mm).

The maximum PCB size is 400mm X 500mm,and it can be a single board of this size or multiple designs on a panel.

We provide various solder mask options, including Green, Black, Blue, Yellow, Red, Purple, and more.

There is also a wide range of surface finish options available, such as Immersion gold, HASL, Immersion silver, Immersion tin, OSP, ENEPIG, Bare copper, and Pure gold plated, among others.

AD255C PCBs perform exceptionally well in cellular infrastructure base station antennas, commercial satellite radio antennas, and more.

Conclusion

AD255C PCBs are processed using standard equipment and chemical processes to plate, image, and etch circuit patterns. It is important to handle them with care to preserve the post-etch laminate surface, as the remaining topography promotes improved adhesion to solder masks.

Thank you for joining us today. We hope you found the information presented here valuable and informative.