# What is the gain of a rubber duck antenna?

## What is the gain of a rubber duck antenna?

Antenna’s gain ranges from unity to 7 dBi, some antennas are IP67 certified.

**Is a rubber ducky antenna a dipole?**

The cutaway view reveals that it is just a half-wave dipole antenna, with one half of the dipole comprising of the metal casing, and the other half comprising the whip extending from the top of the casing.

### How does a rubber ducky antenna work?

The rubber ducky is an electrically short quarter-wave antenna in which the inductor, instead of being in the base, is built into the antenna itself. The antenna is made of a narrow helix of wire like a spring, which functions as the needed inductor.

**How do you calculate the impedance of a dipole antenna?**

The dipole feed impedance is determined by the ratio of the voltage and the current at the feed point – it is simply calculated using Ohm’s Law. Although a dipole can be fed at any point, it is normal for the feed point to be at the middle of the dipole. This is the current maximum and voltage minimum point.

## How do you measure the length of a quarter wave antenna?

The radiating element is a quarter wave (λ/4) and the radials are 12% longer….1/4 Wave Ground Plane Antenna Calculator.

Quarter Wave Ground Plane Antenna Calculator | |
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Frequency | MHz |

Velocity Factor (see text*) | vf |

Give me the results in… | mm (MilliMetres) cm (Centimetres) m (Metres) in (Inches) ft (Feet) |

A. Vertical Monopole Radiating Element (λ*0.25)*vf |

**What is 5dBi antenna?**

This antenna would typically replace standard 2dBi antennas, which are normally shipped with this class of wireless device, in order to increase the range and/or expand the coverage area. With this 5dBi antenna, theoretically a distance of about 500 meters can be covered. Specifications: • Gain: 5dBi.

### What is flexible antenna?

Rolled type flexible antenna A flexible monopole antenna for UWB systems which can cover the frequency band 3.1 – 10.6 GHz is proposed and fabricated on PET film having the flexible characteristic. To obtain the wide bandwidth, the stepped CPW feed line and the declined shape of the ground plane is used.

**What is the radiation pattern of dipole antenna?**

The radiation pattern of the half-wave dipole is maximum perpendicular to the conductor, falling to zero in the axial direction, thus implementing an omnidirectional antenna if installed vertically, or (more commonly) a weakly directional antenna if horizontal.

## What is the radiation pattern of helical antenna?

The radiated waves are circularly polarized. This mode of radiation is obtained if the dimensions of helix are small compared to the wavelength. The radiation pattern of this helical antenna is a combination of short dipole and loop antenna.

**How do you calculate gain of helical antenna?**

C – Circumference of a turn on the helix antenna (C=pi*D)….Helix or Helical Antenna Gain, Impedance, Diameter.

Antenna Gain Calculation | |
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Antenna Gain (G) | = ( 10.8+10*log(8 * 15) ) / log10 |

Beam Width First Nulls | = 115 / √(8 * 15) |

= 115 / 10.954 | |

= 10.5 degrees |

### What is the gain of a rubber ducky antenna?

Most rubber ducky antennas found on wireless APs and routers have a claimed gain of about 2 – 2.2 dBi. Test results and simulation results confirm that the gain of the half-wave dipole is 2.14dBi. That is, they have 2.14dB gain compared to a hypothetical isotropic antenna.

**What are the rules of thumb for antenna design?**

Rules of Thumb: 1. The Gain of an antenna with losses is given by: 2. Gain of rectangular X-Band Aperture G = 1.4 LW Where: Length (L) and Width (W) are in cm 3. Gain of Circular X-Band Aperture G = d 20 Where: d = antenna diameter in cm 0 = aperture efficiency 4. Gain of an isotr opic antenna radiating in a uniform spherical pattern is one (0 dB).

## Why does the rubber ducky need a ground-plane?

As with many monopole antennas, the Rubber Ducky requires a ground-plane or counterpoise [4] with which to complete its electrical circuit. With handheld transceivers, this ground-plane is often only a small internal shield or the jackets of internal batteries.

**How do you calculate the area of an elliptical antenna?**

Approximating the antenna pattern as an elliptical area: Area of ellipse = B a b = B[ (r sin 2)/2 ][ (r sin N)/2 ]= ( B r2 sin 2 sin N)/4 For small angles, sin N = N in radians, so: The second term in the equation above is very close to equation [3].