RF and Microwave PCB design
RF and Microwave PCB design is considered to be a niche domain requiring exceptional understanding of constrained, exhaustive guidelines and general pitfalls. Selection and placement of components even PCB material if not chosen wisely could cause complete failure of the RF and Microwave PCB design, which could have been done with utmost care at the design phase. We will delve further on RF and Microwave PCB Design and try to understand why it is highly recommended to give your RF and Microwave PCB design projects to only specialized firm.
RF (Radio Frequency) is a part of electromagnetic spectrum having frequencies from 3 kHz to 300GHz with wavelengths ranging from 1 mm to 100 KM, travelling at the speed of light. A part of Radio frequency spectrum between 300MHz to 300GHz is known as Microwave which includes UHF, EHF and SHF band. RF signals can be characterized as high frequency analogue signals. As the signals are analogue in nature and mostly travel over-the-air the amplitude, voltage and current levels are not defined but vary as per environment and medium. To add to the complexity of the analogue signal, its not single frequency but generally band of frequencies so the RF and Microwave PCB design and circuits are designed to pass the desired band and filter out the rest.
Issues and Challenges in RF and Microwave PCB Design
- RF and Microwaves are highly sensitive to noise.
- Matching Impedance is challenging as higher the frequency the lower the tolerance.
- Expects Zero Return loss
- Cross talk is directly proportional to the edge rates of the active line.
- Dissipation factor and dielectric constant value can cause huge losses
- Taking account of Skin Depth loss: At higher frequencies electrons flow on the outer surfaces of the conductor knows as skin effect and causes the effective resistance of the conductor to increase. Continue reading