findLobes

Main, back, and side lobe data

Syntax

L = findLobes(p)

L = findLobes(p,index)

Description

L = findLobes(p) returns a structure, L, defining the main, back, and side lobes of the antenna or array radiation pattern in the specified polar plot, p.

L = findLobes(p,index) returns the radiation pattern lobes from the data set specified in index.

Examples

Find Main, Back, and Side Lobes

Create a dipole antenna and calculate its directivity at 270 MHz.

d = dipole;
D = pattern(d,270e6,0,0:1:360);

Create a polar plot of the dipole directivity. Find the main, back, and side lobes of the dipole antenna.

p = polarpattern(D);

L = findLobes(p)

L = struct with fields:
     mainLobe: [1x1 struct]
     backLobe: [1x1 struct]
    sideLobes: [1x1 struct]
           FB: 0.0170
          SLL: 0
         HPBW: 30.9141
         FNBW: 89.7507
        FBIdx: [216 35.5000]
       SLLIdx: [216 326]
      HPBWIdx: [202 233]
      HPBWAng: [200.4432 231.3573]
      FNBWIdx: [181 271]

Inspect main, back, and side lobe data.

MainLobe = L.mainLobe

MainLobe = struct with fields:
        index: 216
    magnitude: 3.6699
        angle: 214.4044
       extent: [181 271]

BackLobe = L.backLobe

BackLobe = struct with fields:
    magnitude: 3.6529
        angle: 34.4044
       extent: [361 91]
        index: 35.5000

SideLobe = L.sideLobes

SideLobe = struct with fields:
        index: 326
    magnitude: 3.6699
        angle: 324.0997
       extent: [2x2 double]

Find Lobes in Two Data Sets

Create a helix antenna that has a 28 mm radius, a 1.2 mm width, and 4 turns. Calculate and plot the directivity of the antenna at 1.8 GHz.

hx = helix(Radius=28e-3, Width=1.2e-3, Turns=4);
H = pattern(hx,1.8e9,0,0:1:360);
P = polarpattern(H);

Create a dipole antenna and calculate the directivity at 270 MHz.

d = dipole;
D = pattern(d,270e6,0,0:1:360);

Add the directivity of the dipole to the existing polar plot.

add(P,D);

Find the main, back, and side lobes of helix antenna.

L = findLobes(P,1)

L = struct with fields:
     mainLobe: [1x1 struct]
     backLobe: [1x1 struct]
    sideLobes: [1x1 struct]
           FB: 11.1386
          SLL: 11.0829
         HPBW: 56.8421
         FNBW: 172.5208
        FBIdx: [90 270.5000]
       SLLIdx: [90 273]
      HPBWIdx: [61 118]
      HPBWAng: [59.8338 116.6759]
      FNBWIdx: [4 177]

Input Arguments

p — Polar plot

polarpattern object

Polar plot, specified as a polarpattern object. Set the CleanData property of polarpattern to 1 to clean the pattern data by removing any NaN and Inf values before running findLobes function on the data.

Example: polarpattern

index — Index of data set

scalar

Index of data set, specified as a scalar.

Example: 1

Output Arguments

L — Main,back, and side lobe data

structure

Main,back, and side lobe data, returned as a structure.

Data Types: struct

Version History

Introduced in R2016a