A Theory for Electromagnetic Radiation and Coupling

This is latest version of my theory. I have (1)revised the abstract and the Introduction section; (2) added a section for mutual coupling to show that EM radiation and EM mutual coupling are almost the same issue, including figures for mutual couplings, and detailed expressions for the mutual coupling energies; (3)added the real radiative power for the Hertzian dipole; (4) added example of a Yagi antenna; (5) added some detailed parameters for numerical implementation.

Implementation of double-layer loaded on octagon microstrip yagi antenna

A double-layer loaded on the octagon microstrip yagi antenna (OMYA) at 5.8 GHz industrial, scientific and medical (ISM) Band is investigated in this paper. The double-layer consist of two double positive (DPS) substrates. The OMYA is overlaid with a double-layer configuration were simulated, fabricated and measured. A good agreement was observed between the computed and measured results of the gain for this antenna. According to comparison results, it shows that 2.5 dB improvement of the OMYA gain can be obtained by applying the double-layer on the top of the OMYA. Meanwhile, the bandwidth of the measured OMYA with the double-layer is 14.6%. It indicates that the double-layer can be used to increase the OMYA performance in term of gain and bandwidth.

Research and Modeling of Digital Antenna Arrays with Directional Elements on Azimuth-Elevation in VHF Terrain and Vegetation Multipath Propagation Situations

In the paper the problem of using digital antenna arrays equipped with dipole and directive elements simultaneously in the azimuthal and elevation planes is discussed. In particular, they are investigated for communication channels of the VHF range below 1 GHz. This range is characterized by the fact that it has found wide distribution. However, its application is fraught with many difficulties, such as attenuation, reflection from rough surfaces, etc. One of the solutions to these problems can be azimuth-elevation digital beamforming. The paper presents the simulation results for the propagation of signals in the VHF range in free space, two-ray ground-reflection and foliage models. It is assumed that a symmetrical dipole is used on the transmitting side, and a directional Yagi antenna on the receiving digital antenna array (DAA) also equipped with a dipole. The circular (CAA) and hemi-dodecahedron shapes of the arrangement of elements of the receiving digital antenna array are simulated. The bit error rates (BER) depending on the distance between the transmitter and the receiver are estimated for the three above mentioned cases.

Electrodynamics of dual-band end-fed wire dipole radiators

This paper briefly describes an analysis of main electrodynamic characteristics required in design of dual-band Yagi antenna exciters consisting of two electrically thick conductors. The study of end-fed excitation of the said system of conductors allows to predetermine the design of conceptually new circuits of classic dipole radiators, avoiding closely-spaced arrangement of feeding strips that ensure direct excitation of dipole arms and, therefore, reducing their electromagnetic spurious coupling. The latter prevents asymmetry in surface current amplitude distribution on dipole arms and allows to improve its directivity and matching with a power feeder.