# What is the radiation resistance of a half wave dipole antenna?

Table of Contents

## What is the radiation resistance of a half wave dipole antenna?

Radiation resistance of common antennas

Antenna | Radiation resistance ohms |
---|---|

Center-fed half-wave dipole | 73.1 |

Short dipole of length | |

Base-fed quarter-wave monopole over perfectly conducting ground | 36.5 |

Short monopole of length over perfectly conducting ground |

## What is the formula for a half wave dipole antenna?

The length of the total wire, which is being used as a dipole, equals half of the wavelength (i.e., l = λ/2). Such an antenna is called as half-wave dipole antenna. This is the most widely used antenna because of its advantages. It is also known as Hertz antenna.

## What is the radiation resistance of a dipole?

The radiation resistance of a dipole antenna is a simple classical concept which is used to model the power radiated into surrounding infinite space, as explained in many antenna textbooks, e.g. [1].

## How do you calculate the directivity of a half wave dipole antenna?

Electric Current on a half-wave dipole antenna. The directivity of a half-wave dipole antenna is 1.64 (2.15 dB). The HPBW is 78 degrees. , the input impedance of the antenna becomes Zin = 70 Ohms, with no reactive component.

## What is the radiation resistance of loop antenna?

The small loops of a single turn have small radiation resistance (< 1 Ω) usually comparable to their loss resistance. Their radiation resistance, however, can be improved by adding more turns. Also, the small loops are narrowband. Typical bandwidths are less than 1%.

## What is the radiation resistance of quarter wave monopole antenna?

Since a half-wave dipole has a gain of 2.19 dBi and a radiation resistance of 73 ohms, a quarter-wave monopole, the most common type, will have a gain of 2.19 + 3 = 5.19 dBi and a radiation resistance of about 36.8 ohms if it is mounted above a good ground plane.

## What is the radiation resistance of a dipole antenna lambda by 20 long approximately equal to?

Hence option (1) is the correct answer. Length of dipole = λ/2. Directivity = 1.64 or 2.15 dBi.

## How do you measure antenna resistance?

For maximum power to be transferred from the generator to the antenna, the ideal value for the antenna impedance is given by: The * in the above equation represents complex conjugate. So if ZS=30+j*30 ohms, then for maximum power transfer the antenna should impedance ZA=30-j*30 ohms.

## How can you increase the resistance of a loop antenna?

Their radiation resistance, however, can be improved by adding more turns. Also, the small loops are narrowband. Typical bandwidths are less than 1%. However, clever impedance matching can provide low-reflection transition from a coaxial cable to a loop antenna with a tuning frequency range as high as 1:10.