Printed reflectarrays combine certain advantages of reflector antennas and phased arrays. One major hurdle in the designing of reflectarrays is the compensation of phase difference between various elements. This paper presents reviews of various techniques for phase compensation, like using variable sizes of the patch, adding stubs of variable lengths and use of variable size slots on the groun...

-For high frequency and VHF point-to-point communication, the V-antenna reflector and the V-shaped antenna array are useful because of high gain, low cost, easy manoeuvering and simple geometry. The theoretical analysis for the radiation characteristics of a plane, twodimensional, V-shaped antenna array have been presented taking into account the mutual inductive coupling effect among the radia...

Abstract—This paper describes a wideband double-dipole Yagi-Uda antenna fed by a microstrip-slot coplanar stripline transition. The conventional dipole driver of a Yagi-Uda antenna is replaced by two parallel dipoles with different lengths to achieve multi-resonances, and a small, tapered ground plane is used to allow flexibility in the placement of a pair of reflectors for effective reflection...

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...

In this paper, a structure of patch antenna operating at 0.5 GHz is proposed for ground-penetrating radar (GPR) applications, with an optimized performance low frequencies. The was designed using FR4 substrate, 4.4 permittivity value, and tangent loss equivalent to 0.021. prototype design backed by rectangular reflector, which has improved the gain directivity. evaluated in terms return loss, g...

A b s ~ The science objectives o f the HYDROS mission are to provide frequent, global measurements o f snrface soil moisture and surface f r d t h a w state. In order to adequately measure these geophysical quantities, the key instrument requirements were determined by the HYDROS science team to be: 1) Dualp o l a h t i o n L B a n d passive radiometer measurements at 40 km resolution, 2) Dual-...

Abstract—This paper presents a circular ring antenna fed by two perpendicular probes, both of which are placed above the square reflector. The antenna is employed to radiate unidirectional beam for polarization diversity reception. A linear isolator is added to improve the isolation between the two probes. The antenna is proposed for the point-to-point communication of Wireless Local Area Netwo...

The reflector antenna design problem requires to solve a second boundary value problem for a complicated Monge-Ampère equation, for which the traditional discretization methods fail. In this paper we reduce the problem to that of finding a minimizer or a maximizer of a linear functional subject to a linear constraint. Therefore it becomes an linear optimization problem and algorithms in linear ...

The application of conventional reflector-type compact antenna test ranges (CATR’s) becomes increasingly difficult above 100 GHz. The main problems are the tight surface accuracy requirements for the reflectors and, therefore, the high manufacturing costs. These problems can be overcome by the use of a hologram type of compact range in which a planar hologram structure is used as a collimating ...

This article describes the design, fabrication, and measurement of a low-profile beam-steerable transmitarray (TA) antenna based on ray-folding principles. The proposed TA consists planar feeding source, phase-shifting surfaces, metal plate as reflector. electromagnetic (EM) wave radiating from source would first be reflected by then propagate through surfaces to achieve focused beam in specifi...