Centre excited hexagonal cells usea.Yagi uda antennasb.Log-periodic antennasc.Sectored directional antennasd.Omni directional antennas

Centre excited hexagonal cells use sectored directional antennas.

Here's a step-by-step explanation:

1. In cellular communication, the service area is divided into cells. Each cell is served by a base station. The shape of the cell is not a perfect circle but rather a hexagon.

2. Centre excited hexagonal cells refer to the cells where the base station (antenna) is located at the centre of the hexagon.

3. These base stations use antennas to transmit and receive signals. The type of antenna used can vary depending on the specific requirements of the cell.

4. In the case of centre excited hexagonal cells, they typically use sectored directional antennas.

5. Sectored directional antennas are preferred because they can provide coverage to a specific sector of the cell (usually divided into 120-degree sectors). This allows for better control of the signal and reduces interference with other cells.

6. The other types of antennas mentioned (Yagi uda antennas, Log-periodic antennas, Omni directional antennas) are not typically used in centre excited hexagonal cells. Yagi uda and Log-periodic antennas are more commonly used for point-to-point communication, while Omni directional antennas provide coverage in all directions, which is not ideal for a sectored approach.