Thermal Management of High Frequency Circuits by Blind Hole Technology

In a printed circuit board used typically in any advanced type of electronic assembly, significant amount of heat is generated during its operation when it is powered by electrical energy1,2. One way to classify the electronic devices is whether they use any active semiconductor electronic junction or use a high frequency telecommunication circuitry, such as, the one used in radio frequency (RF) or microwave (MW) frequency communication. In the former case, it is the collision of electrons (carriers) with the atoms in the semiconductor that generates the major portion of heat, while in the later case, it is the so called “skin effect” in the copper conductor trace that results in the generation of heat, which, again, nevertheless, is due to the resistance offered to the movement of electrons in the conductor metal. The higher the transmission frequency is, the more pronounced will be the skin effect and temperature rise. Heat is also generated due to the core losses in inductors, transformers and switching losses in high speed transistors.