Effect of air gap on cylindrical dielectric resonator antenna operating in TM/sub 01/ mode

The results of a numerical study on the effect of an air gap on the input impedance and resonance frequency of a cylindrical dielectric resonator (CDR) antenna operating in the TM/sub 01/ mode as a function of dielectric constant are presented. The CDR resides on a conducting ground plane and is excited by a coaxial probe through the bottom of the ground plane. Some of the numerical results are validated experimentally.<>     

A wide axial-ratio beamwidth circularly-polarized oval patch antenna with sunlight-shaped slots for gnss and wimax applications

Wireless Networks - This paper proposes a quadruple band stacked oval patch antenna with sunlight-shaped slots supporting L1/L2/L5 GNSS bands and the 2.3 Ghz WiMAX band. The antenna produces...     

Electromagnetic scattering from composite objects using a mixtureof exact and impedance-boundary conditions

Different surface integral equations for characterizing the electromagnetic scattering from a surface impedance object partially coated with dielectric materials are presented. The impedance boundary condition (IBC) is applied on the impedance surface and the exact boundary condition is applied on the dielectric surface. The resulting integral equations are solved for bodies of revolution using the method of moments. The numerical results are compared with the exact solution for a sphere. Other geometries are considered, and their results are verified by comparing results of the numerical solutions which were obtained using different formulations. The internal resonance problem is examined. It is found that the combined field integral equation (CFIE) can be used at any frequency and with any surface impedance     

Comparative study on the mutual coupling between different sized cylindrical dielectric resonators antennas and circular microstrip patch antennas

A systematic comparative study on the mutual coupling (S/sub 21/) between dielectric resonator antennas (DRAs) and microstrip patch antennas is presented. The mutual coupling between two cylindrical probe-fed DRAs is studied for different radius to height (a/L) ratios. It is found that the mutual coupling decreases with the radius to height ratio. Comparison between mutual coupling of probe-fed cylindrical DRAs and circular microstrip patch antennas with different dielectric substrates are also studied. The mutual coupling between DRAs is 2 dB stronger than between microstrip patch antennas when the patch is etched on a dielectric substrate of a dielectric constant close to the permittivity of the DRA. The mutual coupling of the circular patch antennas reduces with the dielectric constant of the substrate.     

Wideband simple cylindrical dielectric resonator antennas

Bandwidths of the coaxial fed and aperture coupled cylindrical dielectric resonator antennas (DRAs) with broadside radiation patterns are enhanced by exciting the HEM/sub 11/spl Delta// (1相似文献   

Electromagnetic scattering from an eccentric multilayered circularcylinder

Electromagnetic scattering from an eccentric multilayered, homogeneous, circular cylinder is derived rigorously by using a boundary value mode-matching approach. The layers are assumed to be infinite in length and their axes are parallel to each other but their centers may have arbitrary coordinates. The composite arrangement is illuminated by a cylindrical wave from a line source of infinite extent in a direction parallel to the cylinder axis. The problem is two-dimensional and the solution to both types of polarization is presented. The effects of various geometrical and electrical parameters on the near- and far-field patterns are examined     

Accurate impedance model for antiresonant monopoles on finiteground planes

A simple and accurate procedure based upon reaction theory is presented for computing the input impedance of a monopole antenna backed by a finite ground plane. This procedure is used to finally verify theoretically some of the controversial antiresonant measured input impedances presented by Meier and Summers in their classic 1949 work     

Analysis of hard surfaces of cylindrical structures of arbitrarily shaped cross section using asymptotic boundary conditions

The surface equivalence principle is used to formulate the problem of infinitely long cylindrical structures of arbitrary cross section and loaded with metallic strips. The strips are tilted by an angle with respect to the cross section plane. Special cases are considered when the strips are directed along or transverse to the cylinder axis. The excitation is an oblique plane wave incident with arbitrary polarization. The asymptotic strip boundary condition (ASBC) is used to simplify the problem. The surface integral equations are solved using the method of moments. The numerical solution is verified with the series solutions of the circular cylinders loaded with helical strips. Several applications of hard surfaces are presented for structures loaded with tilted strips such as the struts loaded with tilted strips to reduce the equivalent blockage width of the struts and make it polarization independent.