Circularly polarized antennas play an important role in the radio field. Especially in aerospace vehicles, due to the fixed position and attitude of the aircraft, their communication measurement and control equipment requires circularly polarized antennas that are round, lightweight, small and low-cost. Circularly polarized microstrip antenna is an ideal antenna that can meet these requirements. Extended information
Due to the characteristics of radio waves, horizontally polarized signals traveling close to the ground will generate polarization current on the earth's surface. The polarization current generates heat due to the influence of the earth's impedance, causing the electric field signal to rapidly Attenuation, while the vertical polarization method is less likely to generate polarization current, thereby avoiding a significant attenuation of energy and ensuring effective signal propagation.
Therefore, in mobile communication systems, vertical polarization propagation is generally used. In addition, with the development of new technologies, dual-polarized antennas are widely used. In terms of its design ideas, it is generally divided into two methods: vertical and horizontal polarization and ±45° polarization. The latter is generally better than the former in terms of performance, so most of them use the ±45° polarization method.
The dual-polarized antenna combines two antennas with orthogonal polarization directions of 45° and -45°, and works in the transmit-receive duplex mode at the same time, which greatly saves the number of antennas in each cell; At the same time, since ±45° is orthogonal polarization, it effectively ensures good diversity reception effects. (The polarization diversity gain is about 5dB, which is about 2dB higher than that of a single-polarized antenna) This article is copyrighted by Mobile Communications Network.