ABSTRACT

This paper describes the multiband behaviour of several circular-shaped hybrid fractal antennas. Initially, a circular-shaped fractal antenna (antenna-A) is designed and its performance is scrutinised. Afterwards, hybrid fractal approach is utilised in the design process to enhance the operational performance and the resultant structure is named as circular-shaped hybrid fractal antenna (antenna-B). The volumetric dimensions exhibited by the antennas are 38 × 38 × 1.6 mm³. The ground plane dimension ‘L_PG’ has been optimised specifically with a recently developed teaching-learning-based optimisation algorithm. Fabrication and testing of antenna-B is done in order to justify the proposed strategy. Measured results depict that the fabricated antenna operates at six fundamental resonances with acceptable gain values. A bandwidth of 1.97%, 7.47%, 5.46%, 4.04%, 4.37% and 4.53% is evaluated at the respective bands. Radiation patterns provided by antenna-B are arbitrary bidirectional/ omnidirectional. In addition, the influence of specific design patterns on the performance of antenna-B is studied. Experimental measurements are presented and compared with the simulated ones. From practical outcomes, it is suggested that the proposed antenna-B can be useful for several wireless communication applications such as Satellite communication for downlink, Fixed satellite communication, Radiolocation, Direct broadcast satellite communication and Radars.

摘要

本文描述了几种圆形混合分形天线的多频带行为。最初，设计了一个圆形分形天线（天线-A）并对其性能进行了仔细检查。之后，在设计过程中使用混合分形方法来提高操作性能，最终的结构被命名为圆形混合分形天线（天线-B）。天线的体积尺寸为 38 × 38 × 1.6 mm ³。地平面尺寸' L _PG' 已通过最近开发的基于教学的优化算法进行了专门优化。天线-B 的制造和测试是为了证明所提出的策略的合理性。测量结果表明，制造的天线在六个基本谐振条件下工作，具有可接受的增益值。在各个频段评估了 1.97%、7.47%、5.46%、4.04%、4.37% 和 4.53% 的带宽。天线-B 提供的辐射方向图是任意双向/全向的。此外，还研究了特定设计模式对天线-B 性能的影响。给出了实验测量结果并与模拟测量结果进行了比较。从实际结果来看，建议提出的天线 B 可用于多种无线通信应用，例如用于下行链路的卫星通信，