RF Interview Questions 3.0- Microstrip vs Stripline, Coaxial cables, TEM Mode
What the difference between Microstrip, Stripline and Coaxial transmission lines?
One of the early milestones in microwave engineering was the development of waveguides and other transmission lines for low-loss power transmission at high frequencies.
Early RF and Microwave systems relied on waveguides, two-wire lines, and coaxial transmission lines.
Waveguides have the advantage of high-power handling capacity and low loss but are bulky and expensive, especially at low frequencies.
Two-wire lines are inexpensive but lack shielding. Coaxial lines are shielded but are a difficult medium for fabricating complex microwave components.
Planar transmission lines such as stripline, microstrip lines, slot lines, and coplanar waveguides are compact, low cost, and capable of being easily integrated with active circuit devices such as diodes and transistors to form microwave-integrated circuits.
Transmission lines that consist of two or more conductors may support transverse electromagnetic (TEM) waves, characterized by the lack of longitudinal field components. Such lines have a uniquely defined voltage, current, and characteristic impedance.
Waveguides, often consisting of a single conductor support transverse electric (TE) and/or transverse magnetic (TM) waves, are characterized by the presence of longitudinal magnetic or electric field components.
Common interview questions on Waveguides and various transmission lines: