- Material used for the PCB
- Placement of traces
- Placement of planes
- Component interconnections
Materials Used for RF PCBs
- Stability of dielectric constant—Varying from lot to lot and over frequency
- Loss factor—Depending on surface contamination and the hygroscopic nature of the material
- Ability to withstand processing temperatures—Lead-free processing temperatures are higher than regular soldering temperatures
- Thermal conductivity—Even low-power RF circuits can produce a lot of heat
Therefore, selecting a suitable material for making a PCB operating at high frequencies depends on the above factors and the product cost. The choice could range from the low-cost FR-4 material, with its higher loss and not tightly controlled dielectric constant, to FR-4 derivatives with better specifications, or to other specialized low-loss RF material with their well-specified dielectric constant.
- Separate all RF, low-level analog, and digital sections.
- Divide the RF section into circuit groups (amps, LO, VCO, etc.).
- Place all the high-frequency components early in the layout, as this helps to minimize the length of the RF routes (in RF PCBs, functional orientation is more important compared to DFM).
- Place the components carrying the highest frequency next to the connectors.
- Never place unrelated inputs and outputs next to each other. For instance, multi-stage windings should never be placed adjacent.
- When long input or output to RF amplifiers is unavoidable, choose to make the output longer.
- As the trace impedance is a critical factor when trying to control reflections, always match the impedance between the driver and the load, except where the trace is shorter than 1/20th of the wavelength.
- When using pull-up inductors or resistors at the outputs of open-collector devices, always place the pull-up component next to the output pin it is pulling up.
- In addition to decoupling the main power pins of the IC, decouple the pull-up also.
- Inductors usually have large magnetic fields around them-
- Never placed them close together, when in parallel (unless the intention is to couple their magnetic fields)
- Separate all inductors by 1x times the body height (minimum) OR
- Place inductors perpendicular to one another
- Confine “ALL” routes to the section or stage to which they are assigned –
- Digital traces in the digital section
- Low-level analog traces in the low-level analog section
- RF traces in the RF section
- Routing traces into adjoining sections is not recommended
- Route all short RF traces on the component side of the PCB, rout them to eliminate vias
- Place a ground layer below the RF traces.
- Minimize the vias in the RF path, as this reduces the breaks in the ground plane(s) and –
- Minimizes inductance
- Helps contain stray magnetic and electric fields.
- Long controls lines are acceptable, but take care to route them away from RF inputs.
- Keep RF lines away from one another by a minimum distance to avoid unintended coupling & crosstalk.
- Minimum spacing is a function of the acceptable level of coupling, and is good for crosstalk, directional couplers, crosstalk, differential lines coupled in even or odd modes.
Frameless Stencils which are loose foil not with rigis Frames have the advantage of being extremely economical and save tremendous amount of space as well. For Limited Production runs and where budgets are a factor, these are very useful.
1. Patterned border
2. Basic outline border.
Frameless Stencils are laser sliced weld glue stencils intended to work with stencil tensioning frameworks otherwise called Reusable Stencil Frames. Frameless Stencils are noteworthy more affordable than Framed Stencils and lessen storage room necessities.
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PCBPOWER (Subsidiary of Circuit Systems India Ltd) has come a long way ever since it began to manufacture PCBs in 1996 to become one of India’s leading PCB manufacturers today. The company’s high quality and cost effective printed circuit boards with its unmatched consistency and customer-centricity has earned it respect and appreciation on a global level. PCBPOWER has a long-established reputation in providing its customers prototype and small volume through an efficient usage of the state of the art production facility.
One of our major contributions also includes for the development of Electronics Industry through support of:
- Individual Users
- Educational Institutes
With the rapid technological and economical changes, only a flexible organisation can withstand the turbulent circumstances. Flexibility has been our forte. We believe in providing solutions that meet the requirement of our customers and are revolutionary at the same time. Among our ground breaking solutions are a wide range of New Advancements in High Frequency-RF PCBs in Metal Clad PCB’s, RT Duroid and Higher Layer counts with lean manufacturing and SPC. We are a UL certified facility.
Our customers are invaluable to us; their time, money and efforts matter a great deal. We, therefore, strive single-mindedly to minimize the cost, time and efforts of our valued customers, providing them complete solutions concerning PCB fabrication, PCB Layout-Design, Stencil Fabrication through our online ordering & tracking system.
We strive to deliver quality products and services and have a team of creative, experienced and technically competent engineers, designers and staff at PCB POWER and CSIL actively serving the following industries:
- Research & Developments
- Students/ Hobbyist
- Aerospace & Defence
- Educational Institutes
- Industrial Electronics
- Test & Measurement
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