factor affect the design of rectangular microstrip antenna.

[pkg]

Dear Knowledgeable person,

1. What are the factor affecting the design apart from resonant frequency, Er and height of substrate?
2. What the factor defines the antenna,is good or bad apart return loss ?
please share your experience

 

[Positron89]

Hi, your font size is quite small, please use a larger font size

the materials used is also one of the factors that will influence the performance of an antenna. If its a high loss tangent material, then the performance may drop especially in terms of return loss and gain. Here is a thread which focuses on lossy vs loss free materials
https://www.edaboard.com/threads/139884/

It depends on the purposes the antenna is designed. Example, if its a microstrip patch antenna for long range purposes, then the gain as well as the radiation efficiency should be high (high gain antenna). If its a reconfigurable antenna, then the HPBW is also an important factor to be considered. If its an antenna for biomedical purposes such an sensing and etc then the resonant frequency is an important factor as there are appropriate allocations for it.

 

[pkg]

Dear sir,

first of all thank you for share experience.
sir do u have any idea regarding feeding technique except microstrip inset feed.
how can we design L shaped coax ? please share one example.

 

[Positron89]

Hi,

There are a few feeding techniques which can be implemented such as Quarterwave Tx line, coupled feeds and etc. Here's a great link which explains the different feeds to be implemented.
https://www.antenna-theory.com/antennas/patches/patch3.php

Coaxial feed is one of the techniques but it has some disadvantages especially if a thicker substrate is used. I have designed coaxial feeds but not L-shaped designs. If your using CST, there is a documentation folder inside the installed folder. You will find a pdf file on CST MWS. The user manual actually explains on how to design a bended coaxial cable.

 

[pkg]

Dear Knowledgeable Sir/Mam,

what is the effect of current in patch and substrate.Please explain me.

 

[Positron89]

Hi,

If we consider a copper microstrip patch, the material is high conductive and therefore has loosely bound electrons. So what happens is that when a certain voltage is supplied to this patch, the electrons will travel around and this flow is the electric current. The electrons produces electric field around it and when this electrons are moving/accelerated (speed of light) due to the voltage, the field will be disturbed and will try to realign itself around the electrons the same manner when the electron is not moving. So the movement of electrons/charges will eventually produce radiation. The effect of current in the patch is radiation. As changing electric fields produces changing magnetic fields, the results will be electromagnetic radiation.

Substrates in microstrip patches influences the radiation pattern and also the bandwidth. The Er value of the substrate if its lower, the antenna will be able to radiate more efficiently. If the value is too high, the fields in the substrate will be tightly contained and therefore it affects the radiation.

 

[pkg]

Is the dimension of coax feed is depend upon frequency of operation for patch antenna?

 

[khaled.ayman]

No, dimensions remain the same for different frequencies.

In the lab you will always have the same coaxial cable with the same connector for your measurements, whatever the frequency of operation.

That's to the best of my knowledge

And I completely agree that your font size at the beginning is a bit too small, consider making it LARGER :razz: