Varactor-loaded left handed loop antenna with reconfigurable radiation patterns

2009 ◽  
Author(s):  
Q. Liu ◽  
P. S. Hall
Keyword(s):  
Loop Antenna ◽  
Radiation Patterns ◽  
Left Handed

scholarly journals Balanced gain for a square metaloop antenna

2019 ◽  
Vol 6 ◽  
pp. 3
Author(s):  
Hisamatsu Nakano ◽  
Ittoku Yoshino ◽  
Tomoki Abe ◽  
Junji Yamauchi
Keyword(s):  
Frequency Response ◽  
Radiation Pattern ◽  
Free Space ◽  
Loop Antenna ◽  
Circularly Polarized ◽  
Left Handed ◽  
The Difference

A square loop antenna implemented using a metamaterial line, referred to as a metaloop, is discussed. The metaloop radiates a counter circularly polarized (CP) broadside beam when the loop circumference equals one guided wavelength. The frequency response of the gain shows two different maximum values: gain G Lmax for a left-handed CP wave at frequency fGLmax and gain GRmax for a right-handed CP wave at frequency fGRmax, where GLmax is smaller than GRmax. In order to increase GLmax, while not affecting the original GRmax as much as possible (i.e. balance the gain), a parasitic natural conducting loop (paraloop), whose circumference is one free-space wavelength at fGLmax, is placed at height Hpara above the metaloop. It is found that the difference in the gains can be reduced by choosing an appropriate Hpara. The radiation pattern at fGLmax is narrowed by the paraloop, while the VSWR is not remarkably affected.

scholarly journals Metamaterial Inspired Microstrip Antenna Investigations Using Metascreens

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Muhammad Tauseef Asim ◽  
Mushtaq Ahmed
Keyword(s):  
Low Cost ◽  
Cell Structure ◽  
Unit Cell ◽  
Dual Band ◽  
Impedance Bandwidth ◽  
Radiation Patterns ◽  
Wireless Applications ◽  
Left Handed ◽  
Metamaterial Antenna ◽  
Unit Cell Structure

A dual layer periodically patterned metamaterial inspired antenna on a low cost FR4 substrate is designed, simulated, fabricated, and tested. The eigenmode dispersion simulations are performed indicating the left handed metamaterial characteristics and are tunable with substrate permittivity. The same metamaterial unit cell structure is utilized to fabricate a metascreen. This metascreen is applied below the proposed metamaterial antenna and next used as superstrate above a simple patch to study the effects on impedance bandwidth, gain, and radiation patterns. The experimental results of these antennas are very good and closely match with the simulations. More importantly, the resonance for the proposed metamaterial antenna with metascreen occurs at the left handed (LH) eigenfrequency of the metamaterial unit cell structure. The measured −10 dB bandwidths are 14.56% and 22.86% for the metamaterial antenna with single and double metascreens, respectively. The metascreens over the simple patch show adjacent dual band response. The first and second bands have measured −10 dB bandwidths of 9.6% and 16.66%. The simulated peak gain and radiation efficiency are 1.83 dBi and 74%, respectively. The radiation patterns are also very good and could be useful in the UWB wireless applications.

A Novel Right Handed Circular Polarization Folded Reflectarray Antenna at 60 GHz

2017 ◽  
Vol 7 (3) ◽  
pp. 1580
Author(s):  
Mohd Fairus Mohd Yusoff ◽  
Ronan Sauleau ◽  
Zaharah Johari ◽  
Mohamad Kamal A. Rahim ◽  
Huda A. Majid
Keyword(s):  
Reflection Coefficient ◽  
Circular Polarization ◽  
Axial Ratio ◽  
Unit Cell ◽  
60 Ghz ◽  
Radiation Patterns ◽  
Circularly Polarized ◽  
Left Handed ◽  
Antenna Directivity ◽  
Reflectarray Antenna

A novel right-handed circular polarization (RHCP) folded reflectarray antenna with optimized parameters is presented at 60GHz. The RHCP folded reflectarray antenna is designed using left handed circularly polarized selective surface (LHCPSS) Pierrot unit cell. Through simulation, it is shown that the antenna operates well at 60GHz. The maximum antenna directivity is 19dB with a reflection coefficient below -15dB. The radiation patterns showed good responses with side lobes level below -10dB. In addition, the best axial ratio at 60GHz is achieved as 0.75dB.

A Metamaterial Inspired Compact Miniaturized Triple-band Near Field Resonant Parasitic Antenna for WLAN/WiMAX Applications

2021 ◽  
Vol 35 (12) ◽  
pp. 1539-1547
Author(s):  
Si Li ◽  
Atef Elsherbeni ◽  
Zhenfeng Ding ◽  
Yunlong Mao
Keyword(s):  
Near Field ◽  
Loop Antenna ◽  
Dual Band ◽  
Equivalent Circuits ◽  
Pass Band ◽  
Unit Structure ◽  
Left Handed ◽  
Radiation Properties ◽  
Compact Size ◽  
Triple Band

This paper presents a metamaterial-inspired triple-band antenna specified for WLAN and WiMAX applications with a compact size of 24mm × 18mm × 1mm (at 2.4 GHz). It consists of a dual-band left-handed metamaterial (LHM) unit surrounded by a G-style monopole antenna. The LHM is first designed and analyzed with equivalent circuits and simulations. A loop antenna based on the LHM unit is designed and simulated to investigate the radiating performance of the LHM unit structure. We also ran simulations for the G-style monopole. Later, the LHM unit is employed as a near-field resonant parasitic (NFRP) element that surrounded by the G-style monopole. A prototype of this antenna is fabricated. Simulations and measurements were carried out and the results match well, identifying good omni-directional radiating performance. Radiation comparisons with the loop antenna and the G-style monopole indicate that due to NFRP, the G-style monopole’s pass bands are shifted to lower frequencies to satisfy 2.45 GHz and 5.5 GHz bands requirements, meanwhile the LHM unit structure operates a third pass band of 3.5 GHz. The compact size and good radiation properties of the antenna render it suitable for WLAN/WiMAX applications.

Design and Analysis of a New ZOR Antenna with Wide Half Power Beam Width (HPBW) Characteristic

Frequenz ◽  
2017 ◽  
Vol 71 (1-2) ◽  
pp. 41-50 ◽  
Author(s):  
Lin Peng ◽  
Ji-yang Xie ◽  
Xing Jiang ◽  
Cheng-li Ruan
Keyword(s):  
Boundary Conditions ◽  
Transmission Line ◽  
Beam Width ◽  
Unique Characteristic ◽  
Radiation Patterns ◽  
Zeroth Order ◽  
Left Handed ◽  
Field Distributions ◽  
Half Power

Abstract Novel zeroth-order resonator (ZOR) composites epsilon-zero resonance (EZR) and mu-zero resonance (MZR) characteristics was proposed. The proposed resonator was constructed by moving via from centre of the conventional mushroom structure (CMS) to the edge, then, an edge-located via mushroom structure (ELV-MS) was formed. Thus, boundary conditions were transformed from all open-ended to half short-ended and half open-ended. Then, the new ZOR composites EZR and MZR characteristics (called EZR-MZR resonator). Owing to the unique characteristic of the composite EZR and MZR, the proposed ZOR antenna radiates both horizontal-polarized field (uni-directional) and vertical-polarized field (omni-directional). Then, wide half power beam width (HPBW) radiation patterns were realized for the antenna. The deduction and analysis of the proposed EZR-MZR resonator were conducted based on the composite right/left-handed transmission line (CRLH TL) and ZOR theories, and field distributions. The proposed ZOR antenna was investigated with two cases of coupling feeding.

Dual-Band Magnetic Loop Antenna with Monopolar Radiation Using Slot-Loaded Composite Right/Left-Handed Structures

2012 ◽  
Vol E95-B (2) ◽  
pp. 627-630
Author(s):  
Seongmin PYO ◽  
Min-Jae LEE ◽  
Kyoung-Joo LEE ◽  
Young-Sik KIM
Keyword(s):  
Magnetic Loop ◽  
Loop Antenna ◽  
Dual Band ◽  
Left Handed

scholarly journals Ultrasmall Dual-Band Metamaterial Antennas Based on Asymmetrical Hybrid Resonators

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Ji-Xu Zhu ◽  
Peng Bai ◽  
Jia-Fu Wang
Keyword(s):  
Communication Systems ◽  
Dual Band ◽  
Wireless Communication Systems ◽  
Resonant Circuit ◽  
Experimental Demonstration ◽  
Radiation Patterns ◽  
Left Handed ◽  
Dual Band Antenna ◽  
Compact Size ◽  
New Type

A new type of hybrid resonant circuit model is investigated theoretically and experimentally. The resonant model consists of a right hand (RH) patch part and a composite right and left handed (CRLH) part (RH + CRLH), which determines a compact size and also a convenient frequency modulation characteristic for the proposed antennas. For experimental demonstration, two antennas are fabricated. The former dual-band antenna operating at f-1=3.5 GHz (Wimax) and f+1=5.25 GHz (WLAN) occupies an area of 0.21λ0×0.08λ0, and two dipolar radiation patterns are obtained with comparable gains of about 6.1 and 6.2 dB, respectively. The latter antenna advances in many aspects such as an ultrasmall size of only 0.16λ0×0.08λ0, versatile radiation patterns with a monopolar pattern at f0=2.4 GHz (Bluetooth), and a dipole one at f+1=3.5 GHz (Wimax) and also comparable antenna gains. Circuit parameters are extracted and researched. Excellent performances of the antennas based on hybrid resonators predict promising applications in multifunction wireless communication systems.

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