Single input single output system (SISO) is a communication system using a single transmitting antenna and a single receiving antenna, which is the traditional single antenna system. Single input single output antenna system includes SISO Omni Antenna and SISO Directional Antenna.
For traditional single antenna systems, the channel transmission matrix has only one element. The channel transmission matrix is a complex number, not a vector. It can be seen from the formula that when the SNR is relatively high, the capacity increases with the logarithm of SNR. The actual wireless channel is time-varying and will be affected by fading. Due to the influence of fading, SISO channels have smaller capacity values. The unipolar omnidirectional ceiling antenna, no matter it’s SISO Omni Antenna or SISO Directional Antenna, consists of a reflective bottom plate and a radiation vibrator above the reflective bottom plate, a feeding gasket between the reflective bottom plate and the radiation vibrator, and a top loading structure above the radiation vibrator. The top loading structure of the unipolar omnidirectional ceiling antenna is short-circuited and connected to the reflection bottom plate, a fixed connecting piece is connected between the radiation vibrator and the top loading structure, and a space is left between the radiation vibrator and the top loading structure.
Antenna has different radiation or receiving capabilities for different directions in space, which is the directivity of antenna. According to the different directivity, there are two kinds of antennas: omnidirectional and directional. SISO Omni Antennas show uniform radiation at 360 degrees in the horizontal direction, which is commonly referred to as non-directivity. In general, the smaller the lobe width, the greater the gain. SISO Directional Antennas are generally used in communication systems due to the factor of their short distance, large coverage and low price. The gain of SISO Omni Antenna is generally below 9dB. SISO Directional Antennas, in the horizontal direction, show radiation in a certain angular range, which is commonly referred to as directional. Like SISO Omni Antenna, as for the SISO Directional Antenna, the smaller the lobe width, the greater the gain. SISO Directional Antennas are commonly used in communication systems in environments with long communication distance, small coverage, high target density and high frequency utilization rate. We can also think about the relationship between SISO Omni Antenna and SISO Directional Antenna in this way: SISO Omni Antenna can transmit signals in all directions and can receive signals in front, back, left and right. The SISO Directional Antenna is like a reflection surface of the mask behind the antenna. The signal can only be transmitted to the front. The signal sent to the rear is blocked by the reflection surface and reflected to the front, thus enhancing the signal strength in front. When selecting antennas, if multiple stations need to be satisfied and these stations are distributed in different directions of AP, SISO Omni Antenna needs to be adopted. If it is concentrated in one direction, SISO Directional Antenna is recommended. In addition, it is also necessary to consider whether the connector form of the antenna matches the AP and whether the gain of the antenna meets your requirements.