Investigations on possible realization of log periodic dielectric resonator antenna

Abstract

Over the last few decades, a tremendous growth has been seen in the wideband high-frequency communication systems. In addition to other necessary requirements,a compact size, high-efficiency antenna design with low conductor loss is mandatory for enabling high data rate communication. In recent years, Dielectric Resonator Antenna (DRA) has proven to be of exceptional low profile, light weight antenna, which provide wide bandwidth with low dissipation loss compared with microstrip antennas. The gain, bandwidth, and radiation characteristic of DRA can be improved by using array instead of single element DRA. The radiation performance of DRA array can be further enhanced by using log periodic technique.With the growing demand of high speed data transfer and internet access, the communication systems operating in the X, Ku, K and Ka-bands are becoming more prevalent. In this thesis, some DRA array designs based on log periodic technique are investigated experimentally for high frequency wideband applications such as X, Ku, and NATO K-band (K and Ka band jointly known as NATO K-band).The Log Periodic Dielectric Resonator Antenna (LPDRA) array relies on recent developments of wideband DRA array and multi-frequency log periodic technique.The design of LPDRA array is proposed to achieve significant multi-resonant wide bandwidth, with low conductor loss for high frequency applications.The present work deals with the design and analysis of some log-periodic DRA with different feeding methods: Branch microstrip line fed LPDRA; Capacitive coupled LPDRA; Electromagnetically coupled LPDRA and Nine elements LPDRA with dielectric resonators of high relative permittivity as well as with low relative permittivity material.An assay on k-β diagram has also been presented to verify the propagation characteristics of the designed LPDRA array.
The proposed LPDRAs offer continuous operation over a wide bandwidth. It provides high efficiency with low cross polarization level and sufficient gain for practical applications. Due to the inherited advantages of Log Periodic DRA array over single DRAs, the LPDRA designs can have applications at microwave and millimetre wave communication like satellite and radar systems.