As known that inbuilding solution wireless coverage will use omni ceiling antenna, directional coupler, 3dB hybrid coupler, power divider splitter and panel directional antenna.  and where is this original signal from?  There the base station comes, and one kind antenna is used very frequencly at base station.

In the engineering design of mobile communication network, the base station antenna should be selected reasonably according to the actual situation of network coverage, traffic distribution, anti-interference requirements and network service quality.Because the selection of antenna type is closely related to terrain, ground features and traffic distribution, the antenna use environment can be roughly divided into five types: urban, dense urban, suburban, rural areas, traffic trunk lines, etc.1. The urban base station antenna has a high density, and the expected coverage of a single station is small. The following aspects should be considered when selecting the base station antenna:

(1) In order to reduce interference, an antenna with a horizontal half-power Angle close to 60 degrees should be selected.The radiation pattern formed by the antenna is close to the ideal cloverleaf honeycomb structure, and it is well adapted to the existing network, which is helpful to control the crossover switch.As shown in the figure below.

(2) the urban base station generally do not seek a large range of coverage, and pay more attention to the depth of coverage.Because the effective vertical beam of the medium-gain antenna is wider than that of the high-gain antenna, and the effective depth coverage range within the coverage radius is larger, which can improve the indoor coverage effect, the medium-gain antenna is better chosen.

(3) Because the installation space of base station antennas in urban areas is often limited, it is more practical to choose a dual-polarization antenna.

To sum up, urban base stations should choose dual-polarization antenna with medium gain and horizontal half-power Angle of about 60 degrees.An example is a 15dBi dual-polarized antenna with a horizontal half-power Angle of 65 degrees.

2. The selection of antenna for dense urban base station is similar to that for general urban base station.However, as the distance between base stations in dense urban areas is usually only 400 meters to 600 meters, in the case of using a 15DBI dual-polarized antenna with a horizontal half-power Angle of 65 degrees and an effective antenna hanging height of 35 meters, the antenna's lower inclination may be set between 14.0 degrees and 11.5 degrees.At this point, if mechanical downdip is simply adopted, too large inclination Angle will cause the horizontal beam to become wider and the interference to increase. At the same time, the upper sidelobe will also introduce a large interference.The problem of waveform distortion can be solved well by using the electronic inclination antenna, and the interference is relatively small.Therefore, it is more appropriate for base stations in dense urban areas to choose dual-polarization antenna with medium gain and horizontal half-power Angle of electronic inclination of about 60 degrees.

3. In rural areas, in view of the small volume of telephone traffic and the large expected coverage area, the following aspects should be considered when selecting the base station antenna:

(1) For CDMA network, in order to improve the communication quality of the overlapping area of antenna service in two sectors of the directional base station (the overlapping area has the effect of macro diversity) and increase the area of the overlapping area, the antenna with larger horizontal half-power Angle should be selected.For example, an antenna with a horizontal half-power Angle of 90 degrees.

(2) For GSM network, in order to improve the coverage quality, it is better to use the antenna with a larger horizontal half-power Angle in the plain area, but at the same time, it will cause the problem of larger handover region.In mountainous and hilly areas, the antenna with smaller horizontal half-power Angle is easy to control the coverage direction and range, and the effect is better.

(3) In order to ensure the coverage radius, the high-gain antenna should be selected.

(4) Since polarization diversity depends on the distribution of reflectors and scatterers around the mobile station, the effect of polarization diversity is not as good as spatial diversity in rural areas with relatively sparse ground object distribution.Therefore, when the installation conditions are available, the single-polarization antenna should be used as far as possible.

(5) If there is no obvious upward obstruction around the base station, the traffic demand is small, and the expected coverage is small, the omnidirectional antenna can be selected.

In conclusion, the directional base stations in rural areas of CDMA networks should choose high-gain single-polarization antennas with large horizontal half-power Angle, such as 17dBi single-polarization antennas with horizontal half-power Angle of 90 degrees.Directional base stations in rural areas of GSM network should choose high-gain single-polarization antennas with horizontal half-power Angle, such as 17dBi single-polarization antennas with horizontal half-power Angle of 90 or 65 degrees.The omnidirectional base station can choose the omnidirectional antenna of 11dBi.

4, suburban base station antenna suburban situation between the urban and rural areas.For the base station with a large distance, the selection principle of rural base station antenna can be referred to.On the contrary, refer to the selection principle of urban base station antenna.

5. If the antenna of traffic trunk station covers only the traffic trunk lines such as highways or railways, the figure 8 antenna can be considered.The figure 8 antenna has the following characteristics:

(1) The radiative azimuth diagram of the figure 8 antenna matches well with the shape of the area to be covered by the traffic trunk.

(2) The figure 8 antenna is actually a deformation of the omnidirectional antenna, so there is no need to use a power splitter;

(3) The use of one antenna instead of two sector antennas, the cost is lower.If the coverage target is the main traffic line and the villages and towns on one side, the antenna with a direction Angle of 210 degrees can be used.The radiating azimuth characteristics of this antenna make the antenna lobe can take into account the main traffic lines and villages at the same time, and it has similar characteristics to the figure 8 antenna.