论文快速发表网

社科类论文科技类论文医学类论文管理类论文教育类论文农林类论文新闻类论文建筑类论文文艺类论文法学类论文

EI Compendex Source List（2022年1月） EI Compendex Source List（2020年1月） EI Compendex Source List（2019年5月） EI Compendex Source List（2018年9月） EI Compendex Source List（2018年5月） EI Compendex Source List（2018年1月）中国科学引文数据库来源期刊列 CSSCI(2017-2018)及扩展期刊目录 2017年4月7日EI检索目录（最新） 2017年3月EI检索目录最新公布北大中文核心期刊目录 SCI期刊（含影响因子）

本站服务项目浅谈青年教师如何开展教科研大学青年教师如何处理教学和科

论文范文

A Compact Frequency Reconfigurable Hybrid DRA for LTE/Wimax Applications 时间:2017-09-28 12:03   来源:未知   作者:admin   点击: 次 Abstract:A compact hybrid antenna structure with frequency reconfiguration capabilities is presented in this article. The proposed design employs a combination of a rectangular DR element and a coupling slot on the structure’s ground plane (GP). The slot shifts the fundamental DRA mode by introducing a slow wave effect and its resonant behavior helps to achieve an omnidirectional pattern at low frequencies. The slot is loaded with a series of PIN diode switches whose ON/OFF combinations alter the effective slot length. Slot loading with PIN diodes results in frequency reconfiguration of the proposed structure with a large tuning range of 76.2% (between 1.73 and 3.86 GHz). A parametric analysis was performed to investigate the effects of slot length, width, and position on the reflection coefficients of the proposed structure. A prototype of the proposed design was fabricated and results were measured. The measured results show a close agreement with the simulated ones. The proposed design is suitable for DCS 1800 MHz, PCS 1900 MHZ, UMTS, LTE 2500–2700 MHz, and Wimax 3.5 GHz.
1. Introduction
Wireless devices nowadays support multiple application bands including GSM850/900, PCS, DCS, and WCDMA [1]. Moreover, the recently proposed Long Term Evolution (LTE) offers high data rates, greater system capacity, coverage, and improved efficiency by incorporating high performance antennas [2]. Fortunately, simultaneous operation is not required in all service bands. This implies that an antenna is supposed to cover a subset of bands at any given instant and subsequently to cover a different subset. Therefore, the frequency reconfigurable antennas have wide applicability and are able to provide multiband coverage by altering their resonance frequency and/or the impedance bandwidth [3, 4].
Dielectric resonator antennas have recently attained much attention owing to multiple characteristics that include wide impedance bandwidth, low cost, high radiation efficiency, and ease of fabrication. Their design process is flexible offering a control over numerous design parameters like shape, size, aspect ratio, and permittivity.
Antenna miniaturization is becoming a fundamental requirement for wireless applications. Small, efficient, and multiband antennas must be developed which can satisfy the multiple application requirements and can easily be integrated into mobile devices. The absence of miniaturization techniques, particularly at low frequencies, makes the integration impractical for portable devices. Antenna miniaturization techniques for DRAs include C-shaped slotted ground plane [5], use of copper sheet on DRA face [6], metalized upper and lower part of rectangular DRA [7], and stacking of dielectric resonators [8]. All these techniques though successfully reduce the antenna size, the 3D DRA geometry yet poses severe constraints for integration into compact hand-held devices.
  Hybrid antenna structures (combining more than one radiating structure) present a fascinating solution for size reduction as well as a multiband operation. A combination of two ring-shaped slots and a conical shape DRA [9], a combination of T-shaped microstrip line and a circular DRA [10], CPW fed dual band DRA [11], coaxial probe fed RDRA [12], and a combination of moon-shaped defected ground structure with a circular DRA [13] are a few examples of hybrid structures.
   In this article, a novel miniaturized reconfigurable hybrid structure consisting of a rectangular DR element coupled with a GP slot is presented. The GP slot acts as a radiator and also assists in shifting the fundamental mode of the DRA by introducing slow wave effect. The combination (of DR and slot) significantly reduces the antenna size and tunes the structure for a multiband operation. As the miniaturization/reconfiguration is achieved through GP slot, there is little effect on the cross-polarization levels.
Section 2 describes the antenna configuration, while the operating principle along with mathematical formulation is presented in Section 3. Section 4 presents a comprehensive analysis of the proposed structure along with parametric details. The tuning capabilities of the proposed antenna are detailed in Section 5, while Section 6 is dedicated to providing the measurement results. Finally, Section 7 concludes the current communication.