PCB Circuit Materials Selection and Its Influence in Different Frequency Bands of 5G

5G pcb

 

As 5G, IOT and other applications will adopt higher frequency, from the past 3GHz to 6GHz or even 2-30 GHz, this will bring a new technical trend for 5G antenna RF materials. Below is some discussion about how to select pcb circuit material and its influence in different frequency band of 5G:

 

Q1: If it is 24GHz power amplifier, what material is recommended?

Consider the Rogers RO4350B / RO4835 materials and their LoPro versions first, and if the performance is not adequate, consider upgrading less lossy panels such as RO3003, etc.

 

Q2: which substrate material is more advantageous for future millimeter-wave antenna materials for 5G?

The 5G antenna boards can focus on the RO4730G3 material, which is a patented product of hollow silicon ball filler of hydrocarbon resin system, with excellent electrical, mechanical and thermal properties.

 

Q3: RO4450T™ and RO4450B™, whats the difference with them?

On the one hand, the thickness is different, the RO4450T material has the option of 3 mil, 4 mil, 5 mil, while the RO4450B material only 4 mil, on the other hand, there are minor changes and upgrades in the formula, such as better fluidity.

 

Q4: What properties does TCDk restrict the material? Could you explain TCDk?

TCDk is the temperature coefficient of the dielectric constant of the material, that is, how much the dielectric constant Dk becomes at high and low temperatures, which will affect the performance of the designed product at high or low temperature. For example, a bandpass filter for microstrip lines.

5G PCBA

Q5: Generally speaking, the roughness of copper foil is more accurate by using RA,RQ or RZ as the standard.

Copper foil roughness has different definitions, closely related to electrical properties such as loss is called RQ root mean square value, other RA,RZ is usually given by the copper foil supplier parameters.

 

Q6: Can you recommend circuit board materials that are suitable for 100GHz or above?

Please refer to RO3003 material, DiClad 880 material, RT/duroid 5880 material and so on low loss high frequency sheet.

 

Q7: What materials are recommended for 60-70GHz?

Also according to your specific application scenarios and indicators to determine. Generally speaking, priority can be given to materials such as RO4350B / RO4835 and their LoPro versions, followed by less lossy panels such as RO3003 materials

 

Q8: Recently, mmWave has some articles dealing with the through hole technology in different filling ways. Does Rogers have any research results and suggestions on the perforation process technology?

 

Rogers' research on the impact of mmwave holes is available on the official website Technology Support Hub for https://www.rogerscorp.com/acs/technology/index.aspx,.

 

Q9: What's the difference between Dielectric Constant (Process) and Dielectric Constant (Design)?

5G IC

It is a different result under different measurement methods, where Design Dk is a parameter used for actual circuit simulation and design.

 

Q10: Will LoPro technology affect the accuracy of line etching?

LoPro copper foil is smooth compared to general electrolytic copper foil and is helpful for fine circuit etching.

 

Q11: Using microstrip lines, banded lines and coplanar waveguides in different forms, is the use of the Dk in the specification much different from the actual situation?

The Dk on the specification usually refers to the Dk of the medium. In different circuit structures, the equivalent Dk of the circuit is different because of the electromagnetic field distribution. The design Dk on the Rogers specification is based on the value of the microstrip line structure.

 

Q12: How to ensure the performance of the pcb laminate in different humidity environment? Our unit in a relatively large environmental humidity, often encountered in winter and Meiyu day performance has some differences.

 

Moisture absorption is an important indicator of the PCB raw material. There is a water absorption rate in the parameters of the material. The smaller the value, the better. The test method has 23 degrees water immersion for 24 hours and 50 degrees water immersion for 48 hours. In addition, The double 85 test may be harsher for the sheet material.

 

Q13: Below 6GHz, the dielectric constant is usually 3~3.7. What is the main effect of the selection of dielectric constant? When designing SIW filters, in order to reduce the size, can you choose a larger dielectric constant, such as RT/ duroid 601010.2LM material?

 

The difference of dielectric constant will lead to the difference of line width, which will affect the line insertion loss. For antenna applications, dielectric constant also indirectly affects the gain efficiency of antenna. The use of materials with high dielectric constants is a common method for reducing circuit size

ROGERS PCB FOR 5G