With the development of electronic technology, the production of electronic products
requires more and more materials, such as high-frequency materials.
Take Rogers PCB as an example. Rogers PCB material is a kind of high-frequency board
produced by Rogers Company, which is different from conventional PCB board epoxy resin.
It has no glass fiber in the middle and is a ceramic-based high-frequency material. When
the operating frequency of the circuit is above 500MHz, the range of materials available
to design engineers is greatly reduced.
Rogers PCB board is a type of high frequency board produced by Rogers Company, which is
different from the conventional PCB board-epoxy resin. It has no glass fiber in the
middle, and uses ceramic matrix as high frequency material. Rogers PCB material has
excellent dielectric constant and temperature stability, and its thermal expansion
coefficient of dielectric constant is very consistent with that of copper foil, which
can be used to improve the shortcomings of PTFE polytetrafluoroethylene substrate. Very
suitable for high-speed design, as well as commercial microwave and RF applications.
Because of its low water absorption, it can be used as an ideal choice in high humidity
environment, providing customers in high-frequency board industry with the best quality
materials and related resources, and fundamentally controlling product quality.
Generally speaking, Rogers PCB high frequency board can be defined as PCB printed
circuit board with frequency above 1GHz. Its physical performance, accuracy and
technical parameters are very demanding, and it is often used in communication systems,
automobile anti-collision systems, satellite systems, radio systems and other fields.
The Classification of Rogers PCB Board
Material Series
Rogers PCB board material RO3000® series: based on ceramic-filled PTFE circuit
materials, the models are RO3003G2™, RO3003™, RO3203™, RO3035™，RO3006™, RO3010™, RO3210™
Rogers PCB board material RO4000® series: Ro4000 ceramic-filled hydrocarbon laminate and
prepreg is a leading product series in the industry. The models include: RO4003C,
RO4350b, RO4360G2, RO4830, RO4835T, RO4533, RO4534, RO4535, RO4725JXR and RO4730G3.
Rogers PCB board material RT/duroid® Laminate: RT/Duroid® high-frequency circuit
material is a composite laminate containing PTFE filler (random glass fiber or ceramic),
which is suitable for high reliability, aerospace and national defense applications.
Include: RT/duroid® 5880, RT/duroid® 5880lz, RT/duroid® 5870, RT/duroid® 6002,
RT/duroid® 6202, etc.
Rogers PCB board material TMM® series: composite materials based on ceramics,
hydrocarbons and thermosetting polymers, model numbers: TMM3, TMM4, TMM6, TMM10, TMM10i
and TMM13i. etc.
Some Rogers PCB material properties
In rapid PCB prototyping, Rogers PCB is a special circuit board with certain technical
threshold, which is difficult to operate and high in cost. General PCB proofing
factories are too troublesome to make, or because of the small number of customer
orders, they don't want to do it or rarely do it.
Rogers PCB RO4350B material allows RF engineers to design circuits conveniently, such as
network matching, impedance control of transmission lines, etc. Because of its low
dielectric loss, RO4350B has more advantages than ordinary circuit borad materials in
high frequency applications. The fluctuation of its dielectric constant with temperature
is almost the lowest among similar materials. In a wide frequency range, its dielectric
constant is quite stable, 3.48, and the recommended design value is 3.66. LoPra™ copper
foil can reduce insertion loss. This makes the material suitable for broadband
applications.
Rogers PCB RO4003 material can be removed with a traditional nylon brush. Before
electroplating copper without electricity, no special treatment is needed. The board
must be treated with traditional epoxy resin/glass process. Generally, it is not
necessary to remove the drilling hole, because the high TG resin system (280°C+[536°F]])
is not easy to change color during the drilling process. If the stain is caused by
aggressive drilling operation, the resin can be removed by standard CF4/O2 plasma cycle
or double alkaline permanganate process.
The cooking requirements of RO4000 materials are equivalent to those of epoxy
resin/glass. Generally, the equipment that does not cook epoxy resin/glass plate does
not need to cook RO4003 plate. For installing epoxy resin/baked glass as part of the
conventional process, we recommend cooking at 300°F, 250 F (121 C-149 C) for 1 to 2
hours. RO4003 contains no flame retardant. It can be understood that boards packaged in
infrared (IR) units or running at a very low transmission speed can reach temperatures
in excess of 700 F (371 C). RO4003 can start burning at these high temperatures. The
system that still uses the infrared reflux device or other equipment that can reach
these high temperatures should take necessary precautions to ensure that there is no
risk.
RO3003 is a ceramic filled PTFE composite for high frequency circuit materials, which is
used in commercial microwave and radio frequency applications. This series of products
is designed to provide excellent electrical and mechanical stability at competitive
prices. Rogers PCB Ro3003 material has excellent dielectric constant stability in the
whole temperature range, including eliminating the change of dielectric constant when
PTFE glass material is used at room temperature. In addition, the loss coefficient of
Ro3003 laminate is as low as 0.0013 to 10 GHz.
Detailed analysis of Rogers PCB parameters
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1.Rogers PCB board substrate has low water absorption, and high water absorption will
cause dielectric constant and dielectric loss when it is wet.
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2.The thermal expansion coefficients of Rogers PCB board substrate and copper foil must
be consistent, otherwise, the copper foil will be separated during the change of heat
and cold.
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3.The dielectric loss (Df) of Rogers PCB board substrate material must be small, which
mainly affects the quality of signal transmission. The smaller the dielectric loss, the
smaller the signal loss.
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4.The dielectric constant (Dk) of Rogers PCB board substrate must be small and stable.
Generally speaking, the smaller the better, the signal transmission rate is inversely
proportional to the square root of the dielectric constant of the material. High
dielectric constant is easy to cause signal transmission delay.
At present, the global 5G layout is accelerating. Traditional 3G/4G base station
distributed architecture can be divided into BBU, RRU and antenna feeder system, in
which RRU and antenna feeder system are connected by feeder. As the risk of transmission
loss increases with high frequency, the architecture of integrated RRU and antenna
feeder system can reduce the signal loss on the feeder and improve the transmission
efficiency. The high integration makes a large number of scattered components replaced
by PCB boards, which ultimately increases the unit usage of PCB.
High frequency band forces PCB materials to become high frequency.
The 5G era must make use of the high frequency band (3GPP has specified that the
frequency range supported by 5GNR is 450MHz-52.6GHz) because:
1) After the iteration of the first four generations of communication technologies, the
resources in the low frequency band have been occupied, and there are not many resources
available for 5G development;
2) The higher the frequency, the more information can be loaded, the richer the
resources, and thus the higher the transmission rate (for example, only five 20MHz
channels can be divided in 100MHz, while 50 20MHz channels can be divided in 1GHz).
Due to the resonance phenomenon caused by load and the influence of transmission line
effect, the higher the frequency of electromagnetic wave, the more severe the
attenuation will be. To realize efficient transmission at high frequency, it is
necessary to control the loss of signals on the transceiver and transmission devices,
and the corresponding bearing devices will be changed from ordinary plates in the past
to high-frequency plates (such as Rogers PCB RO4350 material). Specifically, the
terminal antenna originally used FPC (flexible printed circuit board) with PI as the
main material, but due to the dielectric constant (Dk, The ability of medium to block
electrons) and dielectric loss (Df, the ability of transmission medium to convert
electric energy into heat energy) are both high, so the transmission efficiency is low.
Therefore, the trend of replacing PI with liquid crystal polymer (LCP) with lower Dk and
Df is becoming increasingly prominent. At present, LCP has been introduced into Apple
mobile phones, and LCP materials are expected to become mainstream materials in the
future. Taking Apple as an example, the single LCP module in iPhoneX is about 4-5
USD/antenna.
The base station also needs high-frequency materials (such as Rogers PCB RO4350
material). At present, the mainstream scheme is to use polytetrafluoroethylene (PTFE) or
hydrocarbon PCB (with very good dielectric properties). The unit cost is increased by
about 1.5-3 times. The high-frequency AC board is needed in the 3G/4G base station RRU.
Among them, high-frequency materials (such as Rogers PCB RO4350 material) are needed for
PCB of RF power amplifier. The demand for high frequency (such as Rogers PCB RO4350
material) of PCB board for 5G AAU medium and high frequency AC board will increase, and
the amount of high frequency materials used in PCB board will increase, thus increasing
the value of single board.
High-frequency PCB board is a special kind of copper clad laminate with high-frequency
microwave substrate, also called high-frequency microwave PCB board, which can be made
into high-frequency PCB by further processing. Rogers PCB board made of Rogers PCB
high-frequency material is widely used in communication base station and antenna
aviation, with high demand and promising market prospect.
As the world's leading supplier of special plates, Rogers Board has a global market
share of over 50%, and has 20 years of industry experience in the field of base station
antenna radio frequency. The company has set up a third R&D center in the United States,
focusing on the R&D of 5G products, and has launched a high-frequency board for 5G
antenna RF. With the expansion of 5G commercial scale, the company is about to usher in
high performance flexibility.
The market is aware that 5G has a large demand for high-frequency boards, but it doesn't
know that the biggest demand elasticity is Rogers PCB board for base station antennas.
As the frequency band of 5G application is higher than 4G, it is necessary to adapt to
the Rogers PCB board of millimeter wave, and the development trend of antenna will turn
to multi-reception, multi-transmission and miniaturization. The number of antenna ports
has increased from the traditional 4-port and 8-port to 64-port and 128-port, and the
demand of Rogers PCB board for antenna application has increased dramatically.
After industry research, it is conservatively estimated that the procurement cost of
initialization materials for 5G antenna is 3-4 times that of 4G multimode antenna, and
the number of Rogers PCB board used in multi-receiver and multi-transmitter antenna is
higher than that of multimode antenna. Therefore, the market space of high frequency
board for 5G base station antenna is expanded by at least 4-6 times. With the advent of
5G commercial era, Rogers PCB board market has a broad prospect.
