where c is the speed of light in vacuum, S = E×H is the Poynting vector, E0 and H0 are the amplitudes of the incident electric and magnetic fields, and Z0 = √ μ0/ 0 = 377 Ω (= 4π/c in Gaussian units). We also note that the small antennas are generally well described by their electric and magnetic dipole moments. So, we consider here the cases of a small linear dipole antenna, for which only its...

The current work covers the evaluation of ultrasonic and electromagnetic (EM) techniques applied to temperature measurement and flow characterization for Enhanced Geothermal System (EGS). We have evaluated both ultrasonic techniques and microwave radiometry for temperature gradient and profile measurements. A waveguide-based ultrasonic probe was developed to measure the temperature gradient. A ...

This paper is focused on the analysis of the current distribution of symmetrical full-wave dipole antenna based on double and triple feeding techniques; the current distributions were measured using a shielded loop protruding through a slit in the antenna surface along its axis, gives exact and accurate measurement rather than sinusoidal approximation. However, the sinusoidal distributions of c...

In this paper, frequency-tunable microstrip antennas, for cognitive radio applications, are proposed. The approach is based on electrically tuning the antenna’s operating frequency by integrating reconfigurable band pass filters into wideband antenna structures. The design of an open loop resonator (OLR)-based bandstop filter, and its transformation to a bandpass filter, are investigated first....

this paper presents an e-ring shaped printed monopole antenna for uwb applications with dual notched bands performance. in order to generate single frequency band notch function, we applied a u-ring shaped monopole antenna, and by inserting a rectangular ring in the centre of it an e-ring shaped radiating patch created and a dual band-notch function can be achieved. the measured bandwidth of th...

in this paper, a resonant slotted waveguide array antenna with circular boundary has been designed and simulated for mono-pulse airborne radar applications. the antenna parameters are:11% bandwidth in x-band (8.6-9.6ghz),vswr < 2, 38dbi directivity, sidelobes level of - 20db and 3-db beam-widths of 2.1degree. to design this antenna, it is divided into short sections (sub-arrays) each with a uni...

this paper presents the results of a study on the radiation characteristics of a plasma triangular antenna in the vhf band (30-300mhz) applying the method of moment. deriving the current distribution of the antenna, it shows the relationship between radiation characteristics of the plasma antenna and the plasma parameters. both theoretical and numerical results indicate that if the plasma frequ...