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...

In this paper two linear arrays including a linear 1×4 and a planar 2×2 of microstrip patch and half-mode substrate integrated waveguide (SIW) cavity hybrid antenna are introduced and investigated. These are simply implemented using low cost single layer printed circuit board (PCB) process. The array element consists of a rectangular microstrip patch with appropriate dimensions in the vicinity ...

Fractal antennae have very special properties: (1) They are broad band antennae, i.e. they radiate, and detect, very eeciently for a wide range of frequencies. The frequency range is speciied by the smallest and largest size present in the antenna. The radiation, and hence the detection, eeciency depends slowly on frequency between these two limits. (2) They can display considerable gain over n...

The radiation characteristic of plasma antenna is investigated by using the finite-difference time-domain (FDTD) approach in this paper. Through using FDTD method, we study the propagation of electromagnetic wave in free space in stretched coordinate. And the iterative equations of Maxwell equation are derived. In order to validate the correctness of this method, we simulate the process of elec...

In this chapter, we describe a compact array antenna. Beamforming is achieved by tuning the load reactances at parasitic elements surrounding the active central element. The existing beam forming algorithms for this reactively controlled parasitic array antennas require long training time. In comparison with these algorithms, a faster beamforming algorithm, based on simultaneous perturbation st...

It has been suggested by a number of authors that the 2.7K cosmic microwave background (CMB) radiation might have arisen from the radiation from Population III objects thermalized by conducting cosmic graphite/iron needle-shaped dust. Due to lack of an accurate solution to the absorption properties of exceedingly elongated grains, in existing literature which studies the CMB thermalizing proces...

It is well known that the simple theory of helicon waves, in which the electron mass m e is neglected, is valid only if E z also vanishes, a condition which is not satisfied in experiment. Exact solutions of cold plasma theory with finite m e and E z predict the existence of additional highly damped Trivelpiece-Gould (TG) modes, which can greatly modify the nature of helicon discharges. However...

A Rectangular Dielectric Resonator Antenna (RDRA) is theoretically analyzed using the Conventional Dielectric Waveguide Model (CDWM), numerically simulated using the High Frequency Structure Simulator (HFSS) based on the Finite Element Method (FEM) software package and experimentally investigated with the consideration of the fundamental mode TE 111. Antenna parameters under investigation inclu...

A low cross-polarization slot array antenna in the narrow wall of ridge waveguide is presented. A non-angled slot which is created in the narrow wall of the ridge waveguide is considered to be used as radiating resonant slot. The normalized resistance and normalized reactance curves are presented for design purposes. A six element slot array waveguide antenna with ridges on its narrow wall is t...