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 "extinction theorem" is used to prove that the fields of reflector antennas determined by integration of the current on the illuminated surface of the reflector are identical to the fields determined by aperture field integration with the Kottler-Franz formulas over any surface Sa that caps the reflector. As a corollary to this equivalence theorem, the fields predicted by integration of the...

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 presence of gas hydrate and associated gas in the Makran Accretionary Prism, offshore Iran, has been confirmed by various seismic indicators, including the bottom-simulating reflector (BSR), amplitude blanking, and bright spot. The pre-stack analysis and the study of amplitude-variation-with-offset (AVO) attributes are the most reliable tools for semi-quantitative study of gas hydrate and f...

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...

n A new antenna and radar-cross-section measurements facility consisting of four anechoic chambers has recently been constructed at Lincoln Laboratory on Hanscom Air Force Base. One of the chambers is a large compact range facility that operates over the 400 MHz to 100 GHz band, and consists, in part, of a large temperature-controlled rectangular chamber lined with radar-absorbing material that...

An axially corrugated horn antenna with an elliptically shaped taper is proposed for satellite communication applications. This structure is a good candidate for the feed of reflectors and also for improving the electrical properties of reflector antennas. A tapering method is used to justify the horizontal location of the corrugation profile which improves the electrical performance of the pre...

The dual polarized reflector antenna used for satellite communications consists of two reflectors; one reflector is solid, the other consists of metal grid. The structure is complicated and the bandwidth is narrow. This antenna structure can be simplified by removing the metal grid and using the solid reflector together with a thin electromagnetic band gap material pasted to the surface of the ...