Characteristics Of Microstrip Antenna Research Articles

Impedance characteristics of microstrip antennas excited by coplanar waveguides with inductive or capacitive coupling slots

A rectangular microstrip antenna fed by a coplanar waveguide with an inductive or a capacitive coupling end slot is analyzed by using the moment method. Numerical calculations for the input impedances are shown to agree well with those of the measurements. For the purpose of design, a parameter study for the variations of input impedance with length and width of the coupling slot is presented. Differences in the input impedance characteristics between the inductive and capacitive coupling cases are also discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Correction to "Radiation and scattering characteristics of microstrip antennas on normally biased ferrite substrates"

The authors correct several errors appearing in their paper (see Pozar, IEEE Trans. Antennas. Propagat., vol. 40, p. 1084, 1992). First, the sign assumption for /spl kappa/ in the Green's function is opposite that given in equation (1) for the permeability tensor. The sign of /spl kappa/ is directly related to the polarity of the bias field, and is sometimes defined differently by different workers. The convention used in the present work was modified after the derivation of the Green's function, and this change was accounted for in the computer program, but mention of this was neglected in the paper. Thus,/spl kappa/ should be replaced by /spl minus//spl kappa/ in equations (21)-(23). Next, the /spl mu/ that appears in the denominator of equation (24) should actually be /spl mu//sub 0/, and the term /spl I.scapsY/ should be dropped from the second parenthetical terms in both equations (16) and (17). Also, the 1//spl beta//sup 2/ terms in equations (30a) and (30b) should be changed to 1//spl beta/. These errors are only in the printed paper, and do not affect the results presented therein. >

Radiation and scattering characteristics of microstrip antennas on normally biased ferrite substrates

Radiation and scattering characteristics of microstrip antennas and arrays printed on ferrite substrates with a normal magnetic bias field are described. The extra degree of freedom offered by the biased ferrite can be used to obtain a number of novel characteristics, including switchable and tunable circularly polarized radiation from a microstrip antenna having a single feed point, dynamic wide-angle impedance matching for phased arrays of microstrip antennas, and a switchable radar cross section reduction technique for microstrip antennas. Results are obtained from full-wave moment method solutions for single microstrip antennas and infinite arrays of microstrip antennas. A cavity model solution for a circular patch antenna on a biased ferrite substrate is also presented, to aid in understanding the operation of these antennas. >

Microstrip antennas

Microstrip antennas have been one of the most innovative topics in antenna theory and design in recent years, and are increasingly finding application in a wide range of modern microwave systems. This paper begins with a brief overview of the basic characteristics of microstrip antennas, and then concentrates on the most significant developments in microstrip antenna technology that have been made in the last several years. Emphasis is on new antenna configurations for improved electrical performance and manufacturability and on advances in the analytical modeling of microstrip antennas and arrays.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Effect of parasitic element on the characteristics of microstrip antenna

The variations in the sizes and position of a parasitic element with the input impedance and bandwidth of a rectangular microstrip antenna are investigated by the method of moments. An integral equation for the unknown patch current densities is formulated in the spectral domain. The Galerkin procedure is employed to solve for the unknowns. It is found that the input impedance varies significantly with the size and position of the parasitic patch. The result is important for bandwidth enhancement and impedance matching of the microstrip antenna. >

Radiation characteristics of microstrip arrays with parasitic elements

The radiation characteristics of microstrip antennas consisting of one centre-fed patch and several identical parasitic patches are studied experimentally. The configurations investigated include a five-element cross and three- and seven-element linear arrays. A significant increase in gain is obtained by using close interelement spacing, with no degradation in pattern characteristics.

Microstrip antennas at microwave frequencies

Theoretical and experimental work on the radiation characteristics of microstrip antennas has been done at microwave frequencies. The radiation patterns and gains of such antennas have been calculated and verified by-experiment in the X-band.