The high-frequency performance of the reflector antennas is mainly limited by the surface. It has been shown that distortions on different regions of the reflector surface can have different effects on the radiation performance. In other words, degradation of the radiation pattern due to the presence of surface distortions is sensitive to the location and behavior of the surface distortion prof...

The suitability of various radiating systems for generating a directive high power microwave (HPhl ) beam is investigated. It is concluded that offset reflector antenna systems are well suited for this purpose. An HPM reflector antenna may consist of one or two reflectors that are illuminated by single or array feeds. To accurately predict the performance of an HPM reflector antenna, a versatil...

In this paper comparison of Reflector Antenna analyzing techniques based on wave and ray nature of optics is presented for an offset reflector antenna using GRASP (General Reflector antenna Analysis Software Package) software. The results obtained using PO (Physical Optics), PTD (Physical theory of Diffraction), and GTD (Geometrical Theory of Diffraction) are compared. The validity of PO and GT...

This paper presents the design of a tri-mode matched feed horn to remove the beam squinting effects in a circularly polarized offset parabolic reflector antenna. In a conical horn, three modes i.e., TE11, TM11 and TE21 are combined in proper amplitude and phase proportion to obtain a tri-mode matched feed configuration. The proposed tri-mode horn is then used as a primary feed device to illumin...

The future National Polar-orbiting Environmental Satellite System (NPOESS) Microwave Imager/Sounder (MIS), a space-borne conical scanning radiometer, uses an offset main reflector with multiple antenna feedhorns to receive upwelling microwave radiation from the Earth’s surface and atmosphere. The offset reflector approach is a convenient and economic way to achieve the desired antenna footprint...

This paper presents the shaping optimization of an S-band cylindrical offset reflector antenna with cosecant-squared radiation pattern in elevation plane. The cross section of the antenna is mathematically modeled by a polynomial function and optimized by the genetic algorithm to obtain the desired pattern for both TE and TM polarizations. The physical optics method together with the uniform th...

A transient quasi-analytic method is improved to analyze the offset reflector for impulse radiating antenna (IRA) applications. Physical optic (PO) approximation and analytic time transform (ATT) are utilized to investigate the time domain (TD) radiating characteristics of the offset reflector. With the appropriate coordinate transformation, the TD far-field integral problem can be simplified t...

We develop a simple model for a feed horn with a uniformly excited circular aperture at the focus of an offset paraboloidal reflector antenna and compare it with reflector antenna analyses using combinations of circular waveguide TE1n modes. The model demonstrates the deep dip that can occur at the spot-beam center for certain feed diameters and it is used in a design procedure that relates the...

In the last years, the Synthetic Aperture Radar (SAR) systems evolution migrates toward the use of multi-channel systems based on Digital Beam Forming (DBF) techniques [1]. This tendendy allows fulfilling stringent SAR requirements, providing high spatial resolution within a wide swath. Moreover, the combination of DBF techniques with parabolic reflector antennas merges both flexibility and hig...