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?
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.