A.M. Karlov – Dr.Sc.(Eng.), Professor
E.V. Volkhonskaya – Dr.Sc.(Eng.), Associate Professor
E.V. Korotey – Post-graduate Student
The paper presents the results of radiation field simulation of the two-mirror Kassegrain antenna. The parabolic reflector and convex secondary reflector radiation field has been evaluated by means of aperture method and current mode. The application of current method in simulation of two-mirror antenna radiation field without standard numerical methods is completed for the first time. It is established that aperture method gives overestimated results for directivity, aperture efficiency and maximum side-lobe level and underestimated results for width of the directional pattern. The program code generated in MathCAD is open for another feed antenna and frequency range adaptation.
The transition from the traditionally used frequency bands L, S and C to higher frequencies, such as Ku, K and Ka, requires the using of mirror antennas with a width of directional pattern 0.3 degrees or less, and with a gain no less than 55-60 dB depending on the diameter of the main mirror (reflector) of the antenna. Such small values of the width of the directional pattern require high accuracy of the applied methods for estimating the radiation field and the radiation characteristics of the two-mirror antenna, consequently. The comparative analysis of the accuracy of the evaluation of the characteristics of the radiation of a two-mirror Kassegrain antenna with a microstrip log-periodical irradiator with using of the aperture method and the method of surface currents was carried out in this paper.
The analytical results were first received for evaluating the radiation field of a counter-reflector in the form of a hyperboloid of rotation and a two-mirror Kassegrain antenna. They were obtained on the basis of the approach, which was described in scientific and technical sources, for application of these methods to the calculation of a single-mirror antenna, and on the basis of the method , which was developed previously, for estimating the radiation field of a log-periodic microstrip antenna.
Model studies were conducted in two stages. At the first stage, the calculation of the radiation field of the counter reflector was carried out on the basis of the surface current method. At the second stage, on the basis of the results which were obtained, the estimation of radiation field and the radiation characteristics of a two-mirror antenna was carried out using both methods.
The comparative analysis of the obtained radiation characteristics in the framework of both methods allowed to conclude that the aperture method, compared with the surface current method, gives overestimated results in the values of the directional coefficient, the maximum level of lateral lobes and the surface utilization factor, and underestimated results in the meanings of a width of directional pattern by the level of the half-power and by the level of zero radiation. Thus, it can be expected, that the application of this method will result to an even greater discrepancy of the simulation results . The authors recommend to use the surface current method for a detailed analysis of the directional properties of a two-mirror antenna.
- Frolov O.P., Val’d V.P. Zerkal’ny’e antenny’ dlya zemny’x stanczij sputnikovoj svyazi. M.: Goryachaya liniya – Telekom. 2008. 496 s.
- Zuzenko V.L., Kislov A.G., Czy’gan N.Ya. Raschet i proektirovanie antenn. L.: VIKA. 1969. 161 s.
- Drabkin A.L., Zuzenko V.L. Antenno-fiderny’e ustrojstva. M.: Sov. radio. 1961. 816 s.
- Pat. RF 2571607 C1. Mikropoloskovaya logoperiodicheskaya antenna. E.V. Volxonskaya, E.V. Korotej, D.V. Kuzhekin / MPK H01Q 10/11 (2006.01). № 2014129990/08; zayavl. 21.07.2014; opubl. 20.12.2015, Byul. № 35, Prioritet 21.07.2014. 15 s.
- Volxonskaya E.V., Korotej E.V., Kuzhekin D.V. Sravnitel’ny’j analiz napravlenny’x svojstv logoperiodicheskoj vibratornoj antenny’ standarta GSM-900 po rezul’tatam model’nogo i naturnogo e’ksperimentov // Radiotexnika. 2014. № 2. S. 95−98.