When analyzing a millimeter-wave reflector antenna with a small aperture, a short focal length, and a complex structure feed, it is no longer suitable to use the high-frequency approximation method, but the full-wave moment method is used to solve the problem due to its huge computational complexity in the PC. There is still great difficulty in solving the solution on the machine. A new method for calculating the millimeter wave reflection surface is proposed. The geometrical characteristics of the axis asymmetry of the calculation model are fully utilized to establish the rotary body moment method model, and the method is applied to the design of the microwave transmission system. The small-diameter millimeter-wave reflector is on the antenna. Since the mutual coupling between the feed and the main paraboloid is considered in the modeling, the calculation results are in good agreement with the experimental results. Through theoretical analysis and experiment, the designed caliber is O. The 3 m antenna satisfies the specific pattern envelope over the entire angular range, achieving the high performance standard of ETSI Class 3.
As people's demand for wireless communication quality becomes higher and higher, multi-level communication systems are gradually established. In order to enable tight integration of systems or subsystems, it is necessary to stabilize high-speed data transmission systems. The microwave transmission system based on the millimeter wave antenna is favored by people because of its low cost and easy construction. The system requires the millimeter wave antenna to meet the strict directional envelope and good cross polarization resolution, which has always been one of the hot issues in antenna design. The design method of the reflector antenna is basically a high frequency approximation method such as geometric optics and physical optics. For electrically large-sized reflector antennas, it is reasonable to analyze and calculate in this way. For a reflector antenna with a small aperture and a complicated feed structure, the high frequency method is obviously not suitable for application. Literature [1] uses low-frequency methods on the feed, such as moment method, FDTD, etc., and uses high-frequency method on the reflector antenna to calculate the pattern in the vicinity of the smaller main lobe, which gives reasonable results. However, since the effects of the mutual coupling between the feed system and the main reflection surface are not taken into account, for large angle regions, the results often differ greatly from the measurement results. Microwave transmission antennas required by microwave transmission systems are often millimeter-wave reflector antennas with small apertures and short focal lengths, and satisfy certain directional envelope requirements in full space. Since such antennas cannot meet the electrical large-size conditions required by the high-frequency method, and the analysis method is required to accurately solve the far side lobe and the back lobe of the antenna, the high-frequency approximation method cannot be used for solving such problems. At present, the study of electric size and complex structure by moment method is a hot issue in computational electromagnetics. In particular, the literature [6] combines the integrated function method with the moment method to divide the complex structure into several pieces. Solving in turn, although the problem that the moment method cannot be solved is solved, the solution time is still very long.
In this paper, the moment method is used to make full use of the geometry of the axisymmetric reflector antenna. The method of rotating body moment method (BOR MoM) is used to solve the three-dimensional problem into a two-dimensional problem. At present, the design of small-caliber reflector antennas by rotating body moment method has been paid attention to. In [8], a small-caliber microwave antenna was designed by rotating body moment method. The design frequency is 5 GHz. The theoretical results agree well with the experimental results. In this paper, the rotating body moment method is applied to the millimeter wave antenna, which is still relatively rare in the literature. Experiments show that this method can effectively analyze the reflector antenna with axisymmetric structure and solve the analysis and design problem of high performance microwave transmission antenna.
The rotating body is an object obtained by rotating a bus bar around a rotating shaft, and its structural parameters are as shown in FIG. Where Ï, φ, and z are the three components of the cylindrical coordinate; t is the length of the bus; t, φ are the directions in which any point on S increases along t and φ; n = φt; v is the angle between the z and the z axis . For scattering or radiation problems, it is often converted to the calculation of the boundary value of the electromagnetic field, using the electric field integral equation or the magnetic field integral equation. In this paper, the electric field integral equation is used when deriving the matrix equation. For good conductors, the boundary conditions are:
Where: Etan inc is the tangential component of the incident electric field; Etan s is the tangential component of the scattered electric field; J is the induced current on the good conductor. Let the L operator be:
Due to the solution
The object is a shaft rotating body, and the solution current is a periodic function with a period of 2π in the φ direction, and then expanded by the basis functions t'fi(t') and φ'gi(t'), which can be expressed as:
Using the Calgary method, the same test function as the basis function is used, Wmlt=tfl(t)ejmφ, Wmlφ=φgl(φ)ejmφ, and the inner product of the two sides of the equation (6) and the test function are obtained.
Due to the orthogonality of the Fourier series, the inner product of equation (7) is not zero when only m=n. The form in which equation (7) is expanded into a matrix is:
which is:
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