Showing papers on "Metamaterial antenna published in 1984"

Broad-band microstrip antennas using additional resonators gap-coupled to the radiating edges

Abstract: A method for increasing the bandwidth of microstrip patch antennas by incorporating two additional resonators which are gap-coupled to the radiating edges of a rectangular patch is described. A two-dimensional analysis using Green's function and segmentation method is used for analyzing the proposed antenna configurations. A bandwidth as large as five times a single rectangular patch is obtained in S -band. Changes in the radiation pattern over this wide bandwidth are discussed. Experimental results are in reasonable agreement with the analysis.

A theoretical and experimental investigation of annular, annular sector, and circular sector microstrip antennas

Abstract: An analysis is presented for three related shapes of microstrip antenna elements: the annular; annular sector; and circular sector. The method of analysis involves the full expansion of resonant modes within the cavity formed by the radiating patch and the ground plane. Experimental results for representative radiators are also included for comparison.

Nested microstrip arrays

Abstract: An antenna structure in which two or more microstrip arrays are disposed onop of each other to minimize the required space. The shape of the microstrip elements and the polarization thereof are chosen so that the individual elements radiate only in specific areas along the edges of the elements with the remainder of the element having no appreciable electric field concentration. Because of the operating frequency of a microstrip element is a function of the size of the element, a second antenna of smaller higher-frequency elements may be disposed over a larger lower-frequency antenna such that the higher frequency antenna does not cover the areas of the lower antenna that radiate but lies over only those areas having no appreciable electric fields concentrations. Increasingly higher-frequency antennas can be placed on top of the lower-frequency antennas if the foregoing conditions are maintained with respect to all of the covered antennas. This arrangement permits separate feed networks and omnidirectional coverage or directional coverage for each of the arrays independent of the others.

Analysis of a Suspended Patch Antenna Excited by an Electromagnetically Coupled Inverted Microstrip Feed

Abstract: A suspended patch antenna electromagnetically excited by an inverted micros trip line has been studied based on a full-wave transmission line analysis in conjunction with a microwave network theory. The input impedance calculated has been compared with measured data.

Microstrip Spiral Antenna for Local Hyperthermia

Abstract: Several microstrip spiral antenna applicators suitable for local hyperthermia treatment operating at 433 and 915 MHz have been developed. Design and experimental results are compared with other types of applicators. A summary of current clinical experience with these applicators is presented.

The Input Impedance of a Rectangular Microstrip Resonator FED by a Microstrip Network on the Backside of the Substrate

Abstract: Analytical expressions for the input impedance of rectangular microstrip resonators used in the microstrip array antennas, fed by a microstrip network on the backside of the substrate are derived. Using the feeding-technique from the backside of the substrate, microstrip antenna arrays with unequally spaced elements can be built to reduce the sidelobe levels or to built dual frequency antennas with low side lobe levels. The accuracy of the developed formulas is discussed and applications in microstrip antennas with low sidelobe levels and in dual frequency antennas will be demonstrated.

A Slot Antenna Radiating in Muscle

Abstract: This paper is relative to the study of slot antenna radiating on muscle. The results presented point out the necessity to take into account the presence of the microstrip line feeding the antenna. To do so we use a two dimensional spectral Domain Approach in which the basis function used are choosen by reference of previous works relative to the microstrip line with tuning septum.