Optimizing Dimensions of Cassegrain Antenna System with Large Magnification Factor

Abstract

In this paper, computer-aided design methods are used to optimize Cassegrain antenna dimensions in the case that the feed antenna is placed exactly behind the main reflector. Conical corrugated horn antenna is utilized as the feed antenna. Parabolic reflector antenna dimensions are calculated considering link budget initially. Then to reduce blockage effect due to the presence of subreflector in front of the main reflector a mathematical equation is extracted. Considering the complexity and nonlinearity of this equation, we used a numerical method to solve it, and optimum edge angle of the rays emerging from the feed antenna toward the subreflector is obtained. The other geometric parameters of the structure are then specified using the relations governing the structure. A design example is presented that clarifies the method more obviously. In this example, the slant ratio of the horn is chosen arbitrarily equal to 0.2. This example is simulated using FEKO software to verify the theory. Then to investigate the effects of choosing different slant ratio values on the Cassegrain antenna specification, the extracted mathematical equation is solved for different slant ratio values for the design example. Magnification factor, subreflector diameter, and the slant radius of the feed antenna are then calculated in optimum for distinctive slant ratio values, and the results are presented.

KEYWORDS:

• Blockage efficiency
• Cassegrain antenna
• Conical corrugated horn antenna
• Optimization
• Radiation efficiency

Additional information

Notes on contributors

Alireza Sharifi

Alireza Sharifi was born in Malayer, Iran, in 1979. He received the BSc degree in electrical engineering from the Shahid Beheshti University, Tehran, Iran, in 2001, the MSc degree from the Iran University of Science and Technology (IUST), Tehran, Iran, in 2004, and the PhD degree from the Iran University of Science and Technology (IUST), Tehran, Iran, in 2011, all in electrical engineering. In 2013 he joined the Department of Engineering, University of Zanjan, Zanjan, Iran, where he currently serves as an assistant professor of electrical engineering. He has completed several projects on electronic and communication circuits. His research interests include high frequency circuit design, the application of numerical methods in electromagnetics, antennas, microwave circuits, biomedical engineering, and photonics. Dr Sharifi is a member of IEEE since 2008 and also a member of the National Elite Foundation (Society of Prominent Persons in Iran). Email: [email protected], [email protected]