Research On Non-Uniformly Compressed Antennas And Water Antennas

With the comprehensive advancement of 5G and the Internet of Things,there is an increasing demand for the radiation characteristics of the interconnected hub——antennas.The commercial application of 3D printing technology and the emergence of new materials have made the antenna design more imaginative.In this context,the non-uniformly compressed antenna is a very valuable research direction.By non-uniform compression,the current distribution(such as amplitude ratio,phase,etc.)on the antenna and the electromagnetic field distribution around the antenna can be controlled.Thus,we can not only achieve miniaturization,gain enhancement,beam assignment,impedance improvement or new mode introduction of the antenna,but also give the antenna design more freedom.The main work of this paper is:1.The concept of the non-uniformly compressed antenna is proposed.The mechanism of dielectric loading in the central part of the dipole's third mode is analyzed in detail to explore the effect of non-uniform compression.The current distribution is controlled by partial dielectric loading,which in turn effectively controls the radiation pattern.We designed,processed,and tested a non-uniformly compressed slot antenna to verify the concept of nonuniform compression.The design not only achieved high gain but also introduced a new mode to form a wideband,showing the potential of non-uniform compression.2.The dipole is compressed at both ends.And both its size and gain optimized.Its size is reduced by 36% and its gain is increased by 0.65 dB,which breaks the gain limit of the traditional half-wave dipole.Under changing the compressive strength at one end of the dipole,we excite a quadratic mode with a pyramidal pattern at the center.Using the phase change of the input impedance of the partly compressed dipole under different loading dielectric radii,a novel self-phase-shifting circularly polarized antenna with two equal-length orthogonal dipoles is realized.The antenna has the advantages of size and gain.Its circularly polarized radiation performance is good.3.To extend the concept of non-uniform compression,we use distilled water to partially compress the electromagnetic field near the antenna.We designed,processed,and tested a frequency reconfigurable dual-band monopole antenna.The introduction of a water sleeve produced a new current mode that was the same electric size as the original quarter-wave monopole.The characteristic of similar radiation patterns is obtained.Starting from the water sleeve,the utility of the dielectric sleeve and its similarities and differences with the metal sleeve are clarified.The water coplanar waveguide structure is proposed.The compression and guidance of electromagnetic waves by distilled water can effectively improve the impedance characteristic of the antenna.We processed and tested the antenna using commercial 3D printing technology.In addition to compact size and transparency,the antenna had a wide impedance bandwidth and achieved high radiation efficiency at high frequencies.