Design of an efficient miniaturized UHF planar antenna

Abstract

In this paper, the design aspects and the measured results of a novel miniaturized planar antenna are described. Such architectural antenna design is of great importance in mobile military communications where low visibility and high mobility are required. Slot radiating elements, having a planar geometry and capable of transmitting vertical polarization when placed nearly horizontal, are appropriate for the applications at hand. Slot antennas also have another useful property, so far as impedance matching is concerned. Basically, slot dipoles can easily be excited by a microstrip line and can be matched to arbitrary line impedances simply by moving the feed point along the slot. Antenna miniaturization can be achieved by using a high permittivity or permeability substrate and superstrate materials and/or using an appropriate antenna topology. Here, we demonstrate miniaturization by designing an appropriate geometry for a resonant narrow slot antenna. A very efficient radiating element that occupies an area as small as 0 12 0 0 12 0 is designed and tested. Simulation results, as well as the measured input impedance and radiation patterns of this antenna, are presented. This structure shows a measured gain of 0.5 dBi on FR4 substrate, which has a loss-tangent of the order of 0.01. Also, the effect of finite ground plane size on gain and resonant frequency is investigated experimentally.

Analysis of the Proximity Coupling of a Planar Array Quasi-Lumped Element Resonator Antenna Based on Four Excitation Sources

“…Incidentally (according to them), the width w of an impedance sections has only a small effect on the scattering parameters in comparison with the length l, where the height h of the sections is oriented transversely to the current flow. Of particular interest therefore is the definition of Hong where he defined quasi-lumped element as microstrip line short sections and stubs whose physical lengths are smaller than a quarter of guided wavelength at which they operate, and as such, are common components for approximate microwave realization of lumped elements in microstrip filters structures, and are termed quasi-lumped elements [2]. It is on the basis of this definition that the proposed derives its lumped element equivalency.…”

“…These works, though efficient suffer significant large antenna size. However, in [2], the authors reported the design of an efficient miniaturized UHF planar antenna employing spiral slot radiating elements. This work is noteworthy and adequate for UHF applications but suffer serious disadvantage most especially at high frequencies range of applications as it becomes unrealizable due to etching limitations.…”

Novel Unidirectional Slot Antenna With a Vertical Wall

“…Its electrical size can be reduced by the terminal loading method, such as antennas with H-shaped or spiral lines loading slots [19,20]. However, the slot antenna has a bi-directional pattern and is not suitable for many applications that require unidirectional radiation patterns.…”

Miniaturized Microstrip-Fed Circular Split Ring Resonator Antenna

“…Using meander, zigzag or spiral shapes can also reduce the antennas as they increase the electrical length of the antenna in a small area. Up to λ/10 antenna is designed using these shapes [10][11][12][13].…”

“…This results in a demand for similar reductions in antenna size. Therefore researchers investigated different methods for miniaturization of the microstrip antenna [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”