Characteristic Impedance depends on the below parameter

a. Dielectric constant of insulating material (εr) b. Thickness of insulating material (h) c. Width of traces (w) d. Thickness of traces (t)

for more information refer the link https://www.microwavejournal.com/articles/30170-transmission-lines?page=5

Thank you Thippesha

The thickness of the metal has a much smaller effect than the width of the metal and the thickness of the dielectric, but it does have some effect. The empirical formulae for impedance use width, and an effective width can be used in these formulae. The effective width is calculated by a simple formula that includes the thickness.

The impedance( Zo ) is dependent on the width (W) of the trace, the thickness (T) of the trace, the dielectric constant ( εr ) of the material used, and the height (H) between the trace and reference plane .

So, thicker the substrate height will give the wider trace??

It will make it look wider, and give a lower impedance. Look up the formulae, and then you won't need to ask simple questions.

Sure, the strip thickness "t" affects the microstrip characteristic impedance due to the increasing proportion of EM fields in air as "t" increases comparing to substrate thickness. So, the effective dielectric constant increases versus "t". Consequently, the impedance decreases versus "t".

In practice everything happens as if the width of the strip was a little longer than the reality called "effective width" ( weff) that depends on "t" and is defined as: weff (t) = w + delta (w (t)) where the variation delta (w (t)) depends on the concentration of fields in the air caused by the increase in thickness "t" so that if "t" increases both delta(w (t)) and weff increase. Hence, Zc decreases ( since Zc is closely inversely proportional to weff ).

Sure, like idea of Mohamed Lamine Tounsi

Yes

impedance is related to

thickness; the permittivity of the substrate; the width of the fedline; and the frequency

Thickness of metal affects effective width of strip which is affecting impedance. It has a small but definite effect

Permittivity of substat is another affecting factor.

For a precise calculations, it is to be considered seriously

Yes,

in case of increase the dielectric constant the antenna size will decreased but the side effect is reduction in the bandwidth of antenna. So, we will increase the antenna (microstrip) thickness to overcome the bandwidth problem and in the same time this will gives more surface waves.

1. yes, it matters. The working principle of a Microstrip Antena (MA) is based on the assumption that the thickness of substrate (i.e. MA) is thin. If you take thick substrate, Cavity model may not be valid.

2. But, full wave analysis will be valid for thick substrate also. W. Chen has shown (in PhD work, 1993) using spectral domain MoM that imaginary part becomes more inductive. It may be possible to get totally non-zero crossing case (pure inductive imaginary part). The same work can be found in book chapter 1 (Advanced in Microstrip and Printed Antennas_K F Lee_1997)

Yes, the thickness of metal also affects the impedance. The increase in the thickness of metal alters the impact of the surface waves. It generates the fringing field at the edge of the transmission line and provides a change of intrinsic inductance and capacitance. The influence of the ground plane changes the frequency response and in turn impedance of the antenna as a whole.

If you use CST, a fun way to visualize the effects will be to open Macros - Calculate- Calculate analytical line impedance - thin microstrip and then change the thickness values by keeping others fixed. This will give you a good idea on the ranges of change as Malcolm White has mentioned. Meenakshi Kohli

Of course, the thicknes of the microstrip matters

Dear Meenakshi Kohli ,

I will not repeat the answers of the colleagues above but I will discuss the matter from an other point.

Any conductor has a resistance R that is inversely proportional to the thickness.

So, the thickness must not made too small to affect an appreciable resistance.

It must be mad thick enough to impart a negligible resistance in the microstrip line. On the other side because of the skin effect at the higher frequency as the current tends to accumulate at the surface of the conductor as the frequency increases then it is not necessary to make its thickness greater than the double of the skin depth.

These are basics of the conductor thickness sizing.

However from the principle point of view the conductor thickness affects it resistance for the current passage in it.

Best wishes

With reference to the answer of Abdelhalim abdelnaby Zekry

The skin depth for 1 GHz in copper is only a couple of microns, so any thickness above 6 microns does not affect the resistance for microwave signals, particularly because nearly all the current flows on the bottom of the track and top of the earth.

Most of the thickness is there to make the tracks resistant to damage and strong enough to solder to. Usual thicknesses range from 9 microns to 70 microns, from Rogers, for example..

Dear Meenakshi Kohli ,

An another important point that the thickness will affect the stray or the edge capacitance. Namely as the thickness of the conductor increases its stay capacitance increases.

Best wishes