Interact with Polar Plot

This example shows how to interact with a polar plot created using polarpattern object.

Create Polar Plot of Helix Antenna

Create a helix antenna with a 28 mm radius, 1.2 mm width and 4 turns.

hx = helix(Radius=28e-3,Width=1.2e-3,Turns=4);

Calculate the elevation cut of the antenna directivity at 1.8 GHz.

H = pattern(hx,1.8e9,0,0:1:360);

View the polar plot of the antenna directivity.

P0 = polarpattern(H);

Figure Polar Measurement contains an axes object. The hidden axes object contains an object of type line.

Interact with Polar Plot

Hover over the plot. You see a message on top of the plot: Right click to interact with the plot. Right-click anywhere in the Polar Measurement window to display a context menu for interacting with the plot. For example, right-click outside the plot to show the Main context menu. Right-click inside the plot to show the Display context menu.

Regular polar plot

Update Angle and Magnitude Values

The angular values are around the circumference of the polar plot. Right-click any of the angle values to open ANGLE context menu. By default, the angles are displayed CCW (counterclockwise).

Change the resolution from 15 degrees to 10 degrees.

Left figure shows polar plot with open angle context menu and right figure shows polar plot with changed resolution of the angle scale.

The magnitude values are on the radial lines of the plot. Right-click any of the magnitude values to open the MAGNITUDE context menu. Choose properties from the context menu to change the magnitude limits, magnitude ticks, or font size.

Polar plot with open magnitude context menu and magnitude properties UI window.

Add Cursors and Calculate Angle Span

Add cursors at 60 degrees and 105 degrees.

To add a cursor from the MAIN or DISPLAY context menus, select Measurements > Add Cursor. After adding the cursor, place the mouse pointer on the cursor and drag it to 60 degrees.

Left figure shows polar plot with open MAIN context menu and Measurements sub-menu with cursor placed on Add Cursor option. Right figure shows polar plot with an added cursor.

You can also add a cursor by double-clicking on the angle values. Double-click 105 to add a cursor. Right-click the newly added cursor and move the cursor to exact value of 105 degrees.

You can also interpolate the two angle values to 60 degrees and 150 degrees. Right-click on each cursor and choose Interpolate from the CURSOR context menu. To set the angle span, from the MAIN or DISPLAY context menu, select Measurements > Angle Span.

Left figure shows polar plot with CURSOR context menu and mouse pointer placed over Interpolate option. Right figure shows polar plot with the interpolated angle.

Calculate the counterclockwise angle span between 60 degrees and 105 degrees.

Left figure shows polar plot with open MAIN context menu and mouse cursor placed over Angle Span option under Measurements sub-menu. Right figure shows polar plot showing the measured angle span.

Change Lower Limit of Magnitude Scale

You can click on the lowest magnitude value on the plot and drag the mouse pointer radially outward to change it.

Regular polar plot with cursor on the lower magnitude limit Plot with updated lower magnitude value.

Zoom In and Zoom Out

Move the mouse pointer on the plot and scroll to zoom in or zoom out of the plot.

Regular polar plot with cursor on the plot Zoomed polar plot

Rotate Plot

Click on any angle value and drag the mouse clockwise or anticlockwise to rotate the plot.

Regular polar plot with cursor on an angle value. Rotated polar plot

Display Peak Locations

To display the peak locations from the MAIN or DISPLAY context menus, select Measurements > Peak Location.

Left figure shows polar plot with open MAIN context menu and mouse cursor placed over Peak Locations option under Measurements sub-menu. Right figure shows polar plot with marked peaks.

Right-click any of the peak triangles and choose NumPeaks. Increase the number of peaks to 4.

Left figure shows polar plot with open PEAKS context menu and mouse cursor placed over 4 under Numpeaks sub-menu. Right figure shows polar plot with 4 marked peaks.

View Antenna Metrics

Antenna metrics in the polar plot display the main, back, and side lobes of the antenna. There are two ways to turn display antenna metrics on the plot:

1. Right-click within the polar figure to open the Main context menu. Choose Antenna Metrics.

2. Right-click inside the polar plot to open the Display context menu. Inside the Measurement menu, choose Antenna Metrics.

Left figure shows polar plot with PEAK context menu with mouse cursor placed over antenna metrics. Right figure shows polar plot with the following antenna metrics: HPBW, FNBW, F/B ratio, SLL with highlighted main and back lobe

By default, the plot shows the HPBW (half-power beamwidth) of the antenna. The antenna measurements text box displays:

HPBW (half-power beamwidth)
FNBW (first-null beamwidth)
F/B (front-to-back ratio)
SLL (side lobe level)
Main (main lobe peak value and corresponding angle)
Back (back lobe peak value and corresponding angle)

To view the FNBW, right-click inside the red or gray polar plot region to open the MAIN LOBE or the BACK LOBE context menu and then choose First-Null Beamwidth.

Left figure shows different antenna metrics on the polar plot with marked HPBW. Right figure shows different antenna metrics on the polar plot with marked FNBW.