# How to plot radiation pattern in MATLAB (in dB)

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#### si14

##### Full Member level 3 Hi all:

I want to know how to plot radiation pattern in dB (Logarithmic) in MATLAB?

Thanks.

#### Kohi_boy

##### Full Member level 4 1) which version of MatLab
2) What is your INPUTS ??

#### si14

##### Full Member level 3 Hi Kohi_boy:

The version is 2006Ra.
My inputs are angles(rad) and for example Gain in dB or Mag. I export them from HFSS.

• sumimithu

### sumimithu

Points: 2

#### prafuldeo

##### Full Member level 3 3d polar plot matlab

Hello masud_809,

Plotting radiation patterns in matlab is simple but little tricky. I use normalised radiation patterns i.e. max gain is '0' and then it decreases so the scale look likes 0,-5,-10 ...-40(dB) . Other important thing to keep in mind is the POLAR function in matlab do not plot the negative gains and returns you with an error so you have to keep everything positive or zero values.
So to plot the normalised radiation patterns :

1. open your data in excel sheet.

2. look for the max. gain value for particular angle, say for example its 6 dB. Now to make a plot with scale 0 to -40 dB which is most common, add 40-6 i.e 34 to all the gain. This make the highest gain of your result which is 6 dB in our example to 40 dB and other decreases accordingly.

3. Now look for any negative values in gain column and replace it to 'Zero'. Once done now you can plot this normalised radiation pattern data using POLAR command and since you already have angles in radians so just directly use that.
Once you plot the pattern just change the scale in matlab plot as 0 to -40.

Thanks & Regards
Praful

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### fsky

Points: 2

#### si14

##### Full Member level 3 Dear prafuldeo:

Thank you very much for your description! I appreciate your time. I will check it out today.

Cheers.

#### prafuldeo

##### Full Member level 3 matlab plot db

Hello masud_809,
Give it a try and let me know how did it go.

Cheers

### si14

Points: 2

#### AndyECE

##### Member level 5 • ### si14

Points: 2

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#### ksugahar

##### Member level 1 • ### si14

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#### prafuldeo

##### Full Member level 3 I've tried mmpolar function, seems it doesn't support the hold on command so multiple plots in same figure is not possible.

#### mns

##### Junior Member level 3 hi everybody,
can anybody expalin how to make 3D polar radiation pattern in matlab?
I am using UV plot where with mesh(x,y,z) command
x=sin(theta)cos(phi)
y=sin(theta)sin(phi)
ans
z=calculated gain
all are NxN square matrix
But I want to plot in polar form
Thanks

#### prafuldeo

##### Full Member level 3 matlab polar db

Hi mns,
I've never tried 3D polar plots in matlab but seems an interesting exercise. I'll try and let you know.

Regards

#### mostafa ahmed

##### Member level 1 how to plot in matlab

Dear all,
I think you can use sisotool function to draw it.
With my best wishes.

#### nagasravanthi

##### Newbie level 2 Re: how to plot radiation pattern

si14 said:
Hi all:

I want to know how to plot radiation pattern in dB (Logarithmic) in MATLAB?

Thanks.

hai mns..

pls give me idea about taking theta and phi values in matlab as iam doing project on plotting antenna radiation pattern using matlab for all type of antennas...
hope i will get reply soon

thanku

#### si14

##### Full Member level 3 Re: how to plot radiation pattern

nagasravanthi said:
hai mns..
pls give me idea about taking theta and phi values in matlab as iam doing project on plotting antenna radiation pattern using matlab for all type of antennas...
hope i will get reply soon
thanku
Hi:

What do you mean by "taking theta and phi values"?
For this post, as you can see, I used MATLAB to re-plot a radiation pattern which I generated with HFSS.
So my angle data were ready and I just needed a function to SHOW that data in 2d/3d.
Regards

#### nagasravanthi

##### Newbie level 2 can u give me some idea to how to plot radiation pattern for rectangular aperture with a=3lambda,b=2lambda in matlab....hope for the reply...
thnku

#### si14

##### Full Member level 3 nagasravanthi said:
can u give me some idea to how to plot radiation pattern for rectangular aperture with a=3lambda,b=2lambda in matlab....hope for the reply...
thnku
In order to plot the radiation pattern, you need to have the electric(magnetic) fields. There are some classic shapes, for example rectangular apertures with classic radiation patterns.
You can find the radiation pattern for these apertures in any antenna text books. My suggestion is Balanis.
Cheers

• 38600767

### 38600767

Points: 2

#### sriranjani

##### Newbie level 1 hi all,
can anyone say me the commands for plotting the radiation pattern for patch antennas clearly

#### nurulhazlina

##### Junior Member level 1 Hello,

how can i plot radiation pattern of an antenna in Matlab?

thanks

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