Compared with conventional microwave antennas, microstrip antennas have some advantages. Therefore, a large number of applications have been obtained in a wide frequency band from about 100MH to 50GHz. Compared with the usual microwave antennas, some of the main advantages of microstrip antennas are:
The flat structure with light weight, small size and thin profile can be made into conformal antenna; low manufacturing cost, easy to mass production; can be made very thin, therefore, does not disturb the aerodynamic performance of the loaded spacecraft; The antenna can be easily mounted on missiles, rockets and satellites. The antenna has a small scattering cross-section, and linear polarization and circular polarization (left-handed and right-handed) can be obtained by slightly changing the feeding position; it is easier to control Dual frequency. Working antenna; no back cavity required; microstrip antenna is suitable for combined design (solid devices, such as oscillators, amplifiers, variable attenuators, switches, modulators, mixers, phase shifters, etc. Add directly to the antenna substrate); the feeder and matching network can be made at the same time as the antenna structure.
However, compared with common microwave antennas, microstrip antennas also have some disadvantages:
The frequency band is narrow; there is loss, so the gain is low; most microstrip antennas only radiate to half space; the maximum gain is actually limited (about 20dB); the isolation between the feeder and the radiating element is poor; the end-fire performance is poor; possible There are surface waves; the power capacity is low. But there are some ways to reduce certain shortcomings. For example, as long as special attention is paid to the design and manufacturing process, surface waves can be suppressed or eliminated.
Application of microstrip antenna
In many practical designs, the advantages of a microstrip antenna far outweigh its disadvantages. Microstrip antennas have been used in some important systems:
Mobile communications; satellite communications; Doppler and other radars; radio altimeters; command and control systems; missile telemetry; weapon signal tubes; portable devices; environmental detection instruments and remote sensing; feed units in complex antennas; satellite navigation receivers ; Biomedical radiator.
These are by no means a complete list. As the awareness of the application possibilities of microstrip antennas increases, the applications of microstrip antennas will continue to increase.