Microwave Tech - RO4350B and FR4 manufacture low-cost high-frequency PCB

With the development of wireless communication technology, a variety of wireless signals carrying various kinds of information fill people's living spaces. Whether 2G (GSM), 3G (CDMA, WCDMA, TD-SCDMA), 4G (TDD/FDD LTE), WiFi and other wireless signals need to be transmitted from different devices. Take the wireless cellular network system as an example. Regardless of the size of the equipment, there must be a fixed place to establish a base station, place antennas, and ensure that the system and the system will not interfere with each other.

A large number of commercial equipment such as 2G, 3G and 4G are placed together, and even some 3G and 4G small base stations need to be relocated. These all put forward high requirements for the size of the equipment. In addition to the need for chip manufacturers to continuously improve the integration of chips, equipment manufacturers also have higher requirements for printed circuit boards that carry circuit components.

Rogers RO4350B high-frequency PCB materials meet the stringent requirements of commercial equipment manufacturers for printed circuit boards and have strong market competitiveness.

The dielectric constant stability of hydrocarbon ceramic laminate RO4350B is relatively high. The standard value is 3.48 at 10GHz frequency. The dielectric constant will decrease with the increase in frequency. The dielectric constant at 24GHz frequency will decrease by 0.01 compared with 10GHz frequency, which is 3.47.

Rogers RO4350B is a glass fiber-reinforced hydrocarbon/ceramic laminate. Its main advantages are as follows:

Low permittivity tolerance

Low RF loss

Stable electrical characteristics at different frequencies

Low dielectric constant fluctuation with temperature

Low Z-axis thermal expansion coefficient

Expansion coefficient in low plate

Rogers RO4350B is easy to mass produce and FR4 multi-layer mixed press, with high-cost performance

Let's take a look at the RF loss that RF engineers are most concerned about. It not only has good high-frequency performance, low RF loss and other excellent electrical characteristics but also has low production cost. Rogers RO4350B can be mixed with FR4 multilayer and other characteristics and has strong market competitiveness.

First of all, let's take a look at the loss characteristics of Rogers RO4350B in terms of one of the most concerned sheet characteristics of RF engineers: RF loss:

It can be seen from the above figure that at frequencies below 4GHz, the loss per inch of the 20-mil-wide RO4350B 50-ohm microstrip line is less than 0.1dB, which can completely meet the current commercial and civil communication market.

Secondly, let's take a look at the characteristic curve of RO4350B in terms of the temperature characteristic of the dielectric constant, which is the second most important feature of the sheet that RF engineers are most concerned about.

From the above figure, we can see that the change of the dielectric constant of RO4350B is four thousandths in the range of - 50~150 degrees, which lays a solid foundation for the temperature characteristics of communication equipment.

Finally, let's discuss the cost performance of RO4350B. The R&D RF engineers hope that the electrical performance is good and stable; From the perspective of the company's products, the cheaper things are, the better. And now the miniaturization requirements of communication equipment are increasingly endless, forcing RF circuits and digital circuits to be mixed design. So the contradiction arises: how to choose RO4350B and FR4? As a high-frequency plate, Rogers RO4350B has better high-frequency electrical characteristics than FR4, but its price is also higher than FR4.

The problem is solved in this way: RO4350B and FR4 manufacture low-cost high-frequency PCBs. It is only necessary to place the RF part of the equipment on the Rogers RO4350B side and the digital part on the FR4 side. 

We have only analyzed some key characteristics of RO4350B. we can see that RO4350B not only has good high frequency performance, low RF loss and other excellent electrical characteristics, but also has low production cost. RO4350B can manufacture low cost multilayer high frequency PCB and other excellent characteristics with FR4, which can be called a high cost performance high frequency plate. Rogers PCB material is widely used in 5G, mainly RO4730G3 at antenna end, RO4350B at Sub-6G frequency band and RO3003 at 28GHz and other 5G high microwave frequency PCB.