With the development of communications technologies, handheld RF wireless technology has become an increasingly widespread, such as: Wireless pagers, cell phone, wireless PDA, RF Circuit performance indicators which directly affect the quality of the product as a whole. These handheld products one of the biggest is miniaturization, and miniaturization mean that components of the density is greater, which makes components (include SMD, SMC, nude PIX, etc) interfere quite outstanding.

Electromagnetic interference if not handled properly, could cause the entire circuit system does not work, therefore, how to prevent electromagnetic interference and suppression, increases the level of electromagnetic compatibility, design PCB RF Circuit becomes a very important issue. The same circuit, different PCB design, the performance indicators will vary. Protel99SE software to this discussion when the PCB RF Circuit Design Palm products, maximizing circuit performance indicators, in order to achieve electromagnetic compatibility requirements.

Base material of printed circuit board includes both organic and inorganic categories. Performance is the most important substrate dielectric constant ε r, dissipation factor (or dielectric loss) Tan δ, coefficient of thermal expansion CET and moisture absorption rate. Where ε r affect the circuit impedance and signal transmission rate. For high-frequency circuits, more critical factor of the dielectric constant of tolerance is a primary consideration, you should select the tolerance of small dielectric constant substrate.