FAQ's
 

Linear Resonator
Linear Resonator is called as half wavelength linear resonator. Why?
Microstrip linear resonator is an open transmission line that supports a sanding wave at a frequency for which the length of the line is exactly a half wavelength.
Why capacitive coupling gap is required for linear resonator?
To use the resonating structure for measurement, it has to be coupled to an external circuit thus capacitive coupling mechanism is selected for the resonator to couple it to the external circuit.
 

Slot Line
What are slot lines and how they are differ from microstrip line?
A slot line structure is a planar structure, consists of a dielectric substrate, in which a slot is etched on the metallization of the substrate, whereas Microstrip line have one face which is metalized ground and the other (top) face has thin conducting strip of certain width and thickness.
Why the effective dielectric constant for the slot line is less than the substrate permittivity?
The slot line field component is not confined to the substrate only but extended into the air region above the slot and also below the substrate. Thus the energy is distributed between the substrate and the air region. Therefore, the effective dielectric constant for the slot line is less than the substrate permittivity for an infinitely large thick substrate.
 

Microstrip Line
Microstrip Line is also called an open strip line. Why?
In Microstrip Line top ground plane is not present as found in strip line and top surface is open to air. That's why microstrip line is also called as open strip line.
Why are propagating modes along the microstrip line are quasi TEM?
The microstrip line will not support a true TEM wave; at non-zero frequencies, both the E and H fields will have longitudinal components (a hybrid mode). The longitudinal components are small however, and so the dominant mode is referred to as quasi-TEM.