1、 4G antenna: a device that converts high-frequency current or waveguide energy into electromagnetic waves and emits them in a regular direction or converts electromagnetic waves from a certain direction into high-frequency current.
2、 Category of 4G antenna:
1) Classification by use: communication antenna, TV antenna, radar antenna, etc;
2) Classification by operating frequency band: it can be divided into short wave antenna, ultra short wave antenna, microwave antenna, etc;
3) Classification by directivity: it can be divided into omnidirectional antenna, directional antenna, etc;
4) Classification by shape; It can be divided into linear antenna, planar antenna, etc
3、 Omnidirectional antenna, that is, 360 ° uniform radiation in the horizontal pattern, that is, directionless as usual, and beam with a certain width in the vertical pattern. Generally, the smaller the lobe width, the greater the gain.
4、 Directional antenna shows a certain angle scale radiation in the horizontal pattern, which is also known as directionality. In the vertical pattern, it shows a beam with a certain width. Like omnidirectional antenna, the smaller the lobe width, the greater the gain.
4G antenna
5、 Gain refers to the ratio of the power density of the signal generated at the same point in space between the actual antenna and the ambitious radiation unit when the input power is equal. It quantitatively describes the extent to which an antenna concentrates the input power. The gain is obviously closely related to the antenna pattern. The narrower the main lobe of the pattern, the smaller the side lobe, and the higher the gain. The physical meaning of gain can be understood in this way. In order to generate a signal of certain size at a certain point at a certain interval, if an aspiring non directional point source is used as the transmitting antenna, 100W of input power is required. When a directional antenna with a gain of G=13 dB=20 is used as the transmitting antenna, only 100/20=5W of input power is required In other words, the gain of an antenna, in terms of its radiation effect to the large radiation direction, amplifies the input power by a multiple compared with the non directional aspiring point source.
6、 The operating frequency scale (bandwidth) of 4G antenna is always within a certain frequency scale (bandwidth) whether it is a transmitting antenna or a receiving antenna. The bandwidth of the antenna has two different definitions - one is the operating bandwidth of the antenna when the SWR is ≤ 1.5; One is the bandwidth within the scale of antenna gain reduction of 3 dB. In the mobile communication system, it is generally defined according to the previous definition. In detail, the bandwidth of the antenna is the operating frequency scale of the antenna when the SWR of the antenna does not exceed 1.5. Generally speaking, the antenna functions are different at each frequency point within the operation band width, but the function reduction caused by this difference is bearable.