Microstrip line as transmission line How to calculate ribbon line impedance

Compromise to make 1-2GHz match the Smith chart around 50 ohms. I haven't been studying for a long time, and I hope to be high-fingered.

If I want to design a 50 ohm stripline, I have to calculate the width and length based on the frequency, the medium, but now I have two resonant frequencies, for example, one 1 g and one 2 GHz, so if I use a frequency of 1 GHz, then the length and width of the ribbon line is 50 ohms, which can match the excitation of 50 ohms, but at 2 GHz, I still use 1 GHz to calculate the width and length of the ribbon line, then the impedance of the ribbon line is definitely not 50 ohms I don't think it will match the 50 ohm excitation, and what I want to know is how I should choose the frequency to use for the ribbon line calculation, whether it is low frequency or high frequency, or compromise, or whether the ribbon impedance calculation is not about frequency, I hope I can make it clear.

The characteristic impedance of the microstrip line is generally not much related to the relative electrical length of the line width (that is, the characteristic impedance is generally weakly related to the frequency under the fixed physical size), if the thickness of the dielectric board and the physical size of the line width are unchanged, even if the frequency difference is several times, the characteristic impedance is basically stable (Zeland and other companies provide similar calculation tools).

Microstrip line impedance calculation formula: The specific formula is as follows:

What is a microstrip (sky) line, the structure of a microstrip antenna?

A microstrip antenna is an antenna formed by feeding the patch with a thin metal layer on a thin dielectric substrate on one side as a grounding plate, and a certain shape of metal patch on the other side by photolithography etching method.

Microstrip line refers to the microwave transmission line composed of a single conductor band on the dielectric substrate, which is suitable for making a planar transmission line structure of microwave integrated circuits.

Microstrip integrated circuits have the advantages of light weight, small size, wide bandwidth, high reliability, power saving, low cost and long life. It is widely used in modern electronic devices. As the main part of microstrip integrated circuits, the design and calculation of characteristic parameters of microstrip lines have attracted extensive attention.

When designing microstrip devices, it is often encountered to calculate the characteristic impedance of microstrip lines.

At present, there are many methods to analyze the characteristic impedance of microstrip lines, such as the difference method.

Finite element method, conformal transformation method, Green's function method, etc.

The characteristic impedance of the microstrip line, in addition to the effective permittivity.

It is also related to the line width and thickness of the antenna and the thickness design of the dielectric layer.

Transmission lines. As an important breakthrough in microwave transmission technology, microstrip line has the advantages of 3 square digging-level surfaces such as flattening of printed circuits, high dielectric constant substrate materials, and free connection of solid device judgment parts, occupying an important position in microwave transmission.

1.IntroductionMicrostrip integrated circuits have the advantages of light weight, small size, bandwidth, high reliability, power saving, low cost and long life. It is widely used in modern electronic devices.

As the main part of microstrip integrated circuits, the design and calculation of characteristic parameters of microstrip lines have attracted extensive attention [1]. At present, there are many methods to analyze the characteristic impedance of microstrip lines, such as the difference method, the finite element method, the conformal transformation method, the Green's function method, and so on [3]. 2.

The basic principle of the electromagnetic wave propagating on the microstrip line can be approximated as a TEM wave, so its characteristic impedance can be calculated using the following formula: Z0=1CV=%Cl! 1) where c and l are the capacitance and inductance of the unit length of the microstrip line, respectively, and v is the propagation speed of the wave on the microstrip line.

And because the medium does not exist, the propagation speed of the linear wave is the speed of light vc, and vc = 1% lc0! 2) From equation (2), l can be solved as: l=1c0v2c!!

3) Substituting the L value into the equation (1) can find the characteristic impedance z0 of the microstrip line as: z0=1(vc%c0c)!!