# What is the gain of Yagi-Uda antenna?

## What is the gain of Yagi-Uda antenna?

Yagi gain vs number of elements

Approximate Yagi-Uda antenna Gain levels
Number of elements Approx anticipated gain dB over dipole
5 9.5
6 10.5
7 11.5

### What are the disadvantages of Yagi-Uda antenna?

• It is sensitive to frequency.
• It does not offer very high gain limited around 20 dB.
• The design is obstructive in nature.
• Bandwidth is reduced if a number of director element is used in the array.
• Need a large number of elements to be used.
• It is prone to noise.

What is the approximate distance between directors for a Yagi-Uda antenna at frequency 30 MHz?

Explanation: The distance between directors of Yagi-Uda antenna is 0.2λ.

What is the impedance of the Yagi-Uda antenna?

It is observed that the input impedance of the Yagi Uda antenna at centre frequency of 400 MHz is 52 Ω which is very close to 50Ω. Hence good impedance matching is achieved between the antenna and the transmitter and maximum power is transferred.

## What is the advantage of having reflector in Yagi-Uda antenna?

Tis can help in reducing the levels of interference received. Typically a reflector will add around 4 or 5 dB of gain in the forward direction. Director: The director or directors are made to be shorter than the driven element. There may be none, one of more reflectors in the Yagi antenna.

### What is the effect of length of parasitic on radiation pattern?

What effect a parasitic element has on the radiation pattern depends both on its separation from the next element, and on its length. The driven element of the antenna is usually a half-wave dipole, its length half a wavelength of the radio waves used. The parasitic elements are of two types.