findLobes

Class: polarpattern

Main, back, and side lobe data

Description

example

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.

example

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

Input Arguments

expand all

Polar plot, specified as a scalar handle.

Index of data set, specified as a scalar.

Examples

expand all

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: 0.0124
          SLL: 0
         HPBW: 30.9141
         FNBW: 89.7507
        FBIdx: [146 326.5000]
       SLLIdx: [146 36]
      HPBWIdx: [129 160]
      HPBWAng: [127.6454 158.5596]
      FNBWIdx: [91 181]

Inspect main, back, and side lobe data.

MainLobe = L.mainLobe
MainLobe = struct with fields:
        index: 146
    magnitude: 3.6675
        angle: 144.5983
       extent: [91 181]

BackLobe = L.backLobe
BackLobe = struct with fields:
    magnitude: 3.6551
        angle: -35.4017
       extent: [271 361]
        index: 326.5000

SideLobe = L.sideLobes
SideLobe = struct with fields:
        index: 36
    magnitude: 3.6675
        angle: 34.9030
       extent: [2x2 double]

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: 11.1523
          SLL: 11.0997
         HPBW: 56.8421
         FNBW: 172.5208
        FBIdx: [90 270.5000]
       SLLIdx: [90 273]
      HPBWIdx: [61 118]
      HPBWAng: [59.8338 116.6759]
      FNBWIdx: [4 177]

Introduced in R2016a