this article presents an overview of the recent Frequency dependent and Frequency independent antenna theory. An antenna is defined by Webster’s Dictionary as “a usually metallic device (as a rod or wire) for radiating (transmitting) or receiving radio waves or EM wave.” The IEEE Standard Definitions of Terms for Antennas (IEEE Std 145–1983) defines the antenna as “a means for radiating or rece...

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...

in this paper a new low profile substrate integrated waveguide (siw) probe-fed h-plane horn antenna structure with improved gain is proposed. the proposed antenna consists of two waveguides including a rectangular and a taper one, in which both, first and third modes of the structure are simultaneously excited leading to a uniform field distribution along the radiating aperture of the antenna a...

The radiation field from a transmitting antenna is characterized by the complex Poynting vector E x H* in which E is the electric field and H is the magnetic field. Close to the antenna the Poynting vector is imaginary (reactive) and (E,H) decay more rapidly than 1/r, while further away it is real (radiating) and (E,H) decay as 1/r . These two types of fields dominate in different regions in sp...

We introduce here a simple theory of antenna radiation and scattering that fully extends into the time domain a number of standard antenna terms, including gain, realized gain, effective length, antenna pattern, beamwidth, scattering cross section, and radar cross section. Power wave theory applies to linear reciprocal antennas of all feed impedances and feed types, including waveguide feeds. I...