Because of special structure, a dual reflector antenna has beam rotation capability in azimuth and elevation directions. In this structure, the antenna beam can be placed in any point in the space by mechanical movement of twist reflector which it is the most important ability of the antenna. Due to the antenna structure, if the polarization of incident wave is linear, it is expected that the p...

This paper presents the switched-beam slot antenna over the electromagnetic band-gap (EBG) reflector. This antenna is composed of two slot elements fed with phase difference and the EBG reflector, which is applied in order to realize the low profile structure. The radiation characteristics of this antenna are calculated using the FDTD method. The calculated results show that the antenna height ...

In this paper, a directional GPS antenna for L1 frequency 1575 MHz with RHCP and a high directive gain is proposed for indoor positioning applications. The proposed antenna is made of a standard off the shelf GPS patch antenna with an additional conical reflector to enhance the gain and the beamwidth of the antenna. The angle of the cone reflector is optimized by HFSS 11 software. Finally, the ...

To create a next-generation mobile satellite communication system that offers large communication capacity, the onboard antenna system must be a multi-beam system consisting of a light weight 20-m class reflector and a light weight 100-beam class antenna feed system. We clarify that the antenna gain decrease created by the reflector surface distortion in orbit is relatively large. This paper pr...

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...

Unlike metal as conventional Perfect Electric Conductor (PEC) for unidirectional beam reflector, the periodic structures are now attracting more attention form academia and industrial as High Impedance Surface (HIS) or Artificial Magnetic Conductor (AMC) reflector. Because quarter wavelength (λ/4) separation between antenna and PEC reflector is needed for unidirectional beam applications, it in...

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...

An ultra-wideband (UWB) antenna with a novel multilayer frequency selective surface (FSS) reflector is presented. A significant enhancement in the gain has been achieved in a low profile design while maintaining the excellent impedance bandwidth of the UWB antenna. The average peak gain of the antenna has been increased from 4 dBi to 9.3 dBi as a consequence of the use of the FSS reflector. Mor...

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...