1. The Application of Rogers in PCB
Rogers is mostly used in RF microwaves, high-speed designs, military, automotive industries, and mobile apps. Rogers PCB uses dielectric material, which insulates the regular FR-4 based printed circuit boards. For advanced performance and electrical properties, Roger’s article is bound to provide you with low electrical signal loss, dielectric loss, cost circuit fabrication, and outgassing for space applications.
Rogers 4350b laminates use regular glass/epoxy processing but with firm control of dielectric constant and low loss. It is much cheaper than traditional microwave laminates. There is no need for special handling procedures and through-hole treatments.
2. Rogers PCB Thermal Expansion Coefficient
It is common knowledge that things expand when they heat up. In the same way, PCB materials also develop when you subject them to high temperatures. In general, there is a threshold temperature, also called a glass transition temperature, which determines when the expansion starts. The PCB materials will expand when they exceed the set threshold.
So, the coefficient of thermal expansion (CTE) determines how the PCB materials expand after this temperature. Its unit is parts per million (ppm). Rogers 4000 material’s CTE provides circuit designers with many benefits. It is almost equal to copper (in the X and Y direction), allowing the content to show remarkable dimensional stability. This property is critical for the construction of dielectric multilayer circuit boards and temperature-sensitive applications.
Rogers’s material reduces stresses that can cause the warpage of the PCB. They have a glass transition temperature of more than 280°C. Therefore, if you are looking for such CTE characteristics, you may go for Rogers 4000 material series.
3. Rogers PCB Dielectric Constant
Electronic projects with high-frequency components require a stable dielectric constant. By definition, the dielectric constant is the charge quantity that is stored in a material. The PCB material with a high dielectric constant has more voltage and higher capacitance. Rogers’s articles have a stable dielectric constant for a wide frequency range. Thus, it is perfect for broadband applications.
Rogers’s PCB dielectric constant also has a very low temperature coefficient, making it supreme for temperature-sensitive projects. To be specific, Rogers 4350b exhibits a dielectric constant of 3.66. What does this mean? It makes it perfect for point-to-point links in microwave-based projects.
4. Rogers PCB is Hygroscopic
A PCB material should not adsorb moisture from water or air under ideal conditions. But this is not at all practical. Every element is hygroscopic, and so is Rogers PCB. Many modern PCB materials have a moisture absorption rate lying between 0.01% and 0.2%. Therefore, Rogers PCB must absorb minimum moisture.
Fortunately, Rogers PCB already has minimum moisture absorption. This allows them to have better electrical and thermal characteristics. Thus, you can use them for almost every kind of condition and environment. Moreover, Rogers PCBs have lower chances of malfunctioning. The typical value of Rogers 4350b is 0.06.
5. Rogers PCB Temperature Problem
Your project domain decides the max and min bearing temperature of a PCB material. If your electronics project is sensitive to high temperatures, you should go for designs with appropriate Rogers PCB. It should have a reversal mechanism if in case the temperature surpasses the safe limit.
If Rogers PCB temperature problem is ignored, the PCB would likely decay and lose a fraction of its mass. Many applications have an ideal safe temperature limit of up to 350 degrees Celsius. Therefore, you should choose rogers material, which has a decomposition temperature of more than this.
6. Driver Circuit Design Requires Stable Impedance
Driver circuit designs mostly need stable impedance. It is well known that Rogers's material offers a wide range of dielectric constant than the standard FR-4 equipment. Thus, it doesn’t compromise on the performance of such circuit designs by keeping their impedance stable.
Many high-frequency circuits usually work with a characteristic impedance of 50 Ω, and they must match it with other circuit components. This ensures that power transfer is maximum between source and load. Also, the circuits will not get many standing waves and suffer from fewer reflections.
Many contemporary computer-aided-engineering (CAE) software tools allow you to select many parameters of Rogers PCB material. You can define a dielectric constant, using such tools, which ensures impedance matching and stability.
7. Some Practical Applications of Rogers PCB
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Large batch, lower cost
Roger PCB high-frequency laminates have lower cost and allow large batches of PCB materials. It is widespread in automotive radar sensors. Its hybrid PCB uses materials mixture with many layers of flame-retardant FR-4 material. It is also with a high glass transition temperature (Tg). Further, there is even one layer of PCB material that has all the properties required for high-frequency use.
This mixture of PCB materials helps in maintaining reliability, controlling costs, and meeting high electrical performance. The automotive radar sensors have specific performance requirements at 77 GHz frequency. Thus, Rogers material is widely used as the outer layer of high-frequency circuit material. It has all the properties for high performance at millimeter-wave and microwave frequencies.
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Small size and high performance
In electronics, power amplifier design is crucial. The PCB material for an amplifier design must have all the characteristics that would guarantee high amplifier performance. The Rogers PCB is widely in use for high-power amplifiers. They have the right coefficient of thermal expansion, as already discussed, and thermal conductivity.
In the high-power amplifier, you must direct the heat away from the transistors to ensure high performance. Moreover, it would also ensure a long life of such speakers. By definition, the thermal conductivity is “the watts of power per meter of laminate material per degree Kelvin.” Therefore, Rogers PCB would be an ideal PCB material. Rogers 4360b laminate material has a thermal conductivity of 0.62 W/m/K, and Rogers 4360 laminate has a thermal conductivity of 0.8 W/m/K. The laminate with higher thermal conductivity would be able to handle the power better.
8. Understand the Physical Parameters of Rogers PCB
Apart from the parameters discussed above, the hole quality is very crucial when selecting a PCB material. The Roger 4350 material will provide you with good hole quality. But it would help if you made sure that the drills are made according to the glass/epoxy standards. In comparison to glass/epoxy, the irregularity of holes will not increase with usage. It offers a wide range of drilling parameters. Still, you should not exceed the drilling speed of 500 surface feet per minute (SFM).
Metal deposition is another important physical parameter of Rogers PCB. Rogers 4835 and 4835b support the electroless copper processing in addition to no specific preparations before metallization. You would also be able to deposit the colloidal and ionic conductive layers directly.