The Radiation Patterns Produced by a Linear Array of Half-Wave Dipoles Coupled Electromagnetically to a Two-Wire Transmission Line

1962 ◽  
Vol 8 (6) ◽  
pp. 288-297
Author(s):  
Dipak L. Sengupta
Keyword(s):  
Transmission Line ◽  
Linear Array ◽  
Radiation Patterns ◽  
Half Wave

RADIATION FROM A SLOT ON A CYLINDRICALLY TIPPED WEDGE

1954 ◽  
Vol 32 (11) ◽  
pp. 714-721 ◽  
Author(s):  
James R. Wait ◽  
Sidney Kahana
Keyword(s):  
Electromagnetic Field ◽  
Equatorial Plane ◽  
Cylindrical Surface ◽  
Surface Radiation ◽  
Radiation Patterns ◽  
Magnetic Current ◽  
Half Wave ◽  
Infinite Conductivity ◽  
Transverse Slot ◽  
Infinite Wedge

A solution is outlined for the electromagnetic field of a distribution of magnetic current and charge in a volume bounded by an infinite wedge with a cylindrical tip both of infinite conductivity. The result is applied to calculate the fields of a thin half-wave transverse slot on the cylindrical surface. Radiation patterns in the equatorial plane are calculated for wedge angles of 90°, 180°, and 270° for various radii of the cylindrical surface. The results have application to the design of slotted cylinder antennas for directional coverage.

An Easily Realizable Band-Notched UWB Antenna

2013 ◽  
Vol 677 ◽  
pp. 307-310
Author(s):  
Ching Fang Tseng ◽  
Shu Cheng Lu
Keyword(s):  
Transmission Line ◽  
Ground Plane ◽  
Monopole Antenna ◽  
Radiation Patterns ◽  
Uwb Antenna ◽  
Microstrip Transmission Line ◽  
Directional Radiation ◽  
Good Agreement

An easily realizable ultrawideband (UWB) monopole antenna, with band-notched characteristics, is presented. The antenna consists of a circular metal radiation patch, fed by a 50-Ω microstrip transmission line and a rectangular ground plane with a notch cut into it. By etching a modified U-shaped slot in the radiating patch and by properly tuning its location and form, band-rejected filtering properties can be achieved easily in WiMAX/WLAN bands. It has good omni-directional radiation patterns in H-plane and a good agreement between simulation and measurement.

Time-modulated linear array synthesis with optimal time schemes for the simultaneous suppression of sidelobe and sidebands

2021 ◽  
pp. 1-13
Author(s):  
Avishek Chakraborty ◽  
Gopi Ram ◽  
Durbadal Mandal
Keyword(s):  
Antenna Arrays ◽  
High Speed ◽  
Particle Swarm Optimization Algorithm ◽  
Linear Array ◽  
Superior Performance ◽  
Optimal Time ◽  
Radiation Patterns ◽  
Sidelobe Level ◽  
Fair Comparison ◽  
Performance Abilities

Abstract An efficient analysis of time-modulated array (TMA) toward realizing less-attenuating radiation patterns with simultaneously suppressed sidelobe and sidebands is presented in this paper. In this framework, an optimal outer element-controlled time sequence is derived. The proposed time scheme, along with optimized array excitations, is profitably applied for the desired solution. TMAs are considered unconventional alternatives to the phased arrays. The desired array radiation features can be attained by periodically enabling and disabling the array elements through high-speed switches. Despite the advantages of architectural simplicity and real-time reconfigurability of periodic time sequences, time-domain antenna arrays inherently generate unavoidable sideband radiations (SRs). The undesired SRs obtained at multiple harmonics around the carrier frequency of the array resembles power loss in unintended directions. This paper aims to minimize the SRs as well as the sidelobe level (SLL) for an efficient analysis of time-modulated linear array (TMLA) with high-directive radiation patterns. The starting instants and the period of on-times are optimized to generate a unique shifted time scheme for the edge elements of the TMLA to reduce the sideband levels (SBLs). The array excitations and the uniform spacing between the elements are also optimized together with the shifted time scheme for the coveted solution. Other methods of suppressing SLLs and SBLs with shifted pulse schemes and sub-sectioned pulse schemes are also presented for a fair comparison. Modified versions of the particle swarm optimization algorithm (PSO) are applied for the desired solutions. The optimal results attained by wavelet mutation-based novel PSO is compared with the conventional PSO and the modified novel PSO-based results. The representative results are reported, and the superior performance abilities of the proposed method compared to other published studies are assessed.

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.

scholarly journals Design of Linear Array for Shaped Beams using Enhanced Flower Pollination Optimization Algorithm for Marine Radar Applications

2021 ◽  
Author(s):  
Nagavalli Vegesna ◽  
Yamuna G ◽  
Sudheer Kumar Terlapu
Keyword(s):  
Optimization Algorithm ◽  
Optimization Problem ◽  
Linear Array ◽  
Flower Pollination Algorithm ◽  
Far Field ◽  
Radiation Patterns ◽  
Flower Pollination ◽  
Field Radiation ◽  
Radar Applications ◽  
Marine Radar

Abstract In order to generate narrow beams with individual heights of sidelobes, we perform a synthesis of sum patterns. The side lobes can be adjusted to any arbitrary specification and flat top far field radiation patterns using Enhanced Flower Pollination Algorithm (EFPA) is presented in this paper. The problem of designing an array can be expressed as an optimization problem that aims to reduce the first two sidelobes to -50dB and by reducing the remaining sidelobes to -40dB. The EFPA is applied to determine the excitation coefficients of their amplitudes so as to obtain the required pattern. The objective for case 2 is to obtain the flat top sector beam for specified angular regions. Complex excitation coefficients are determined using EFPA for various beam widths. The radiation patterns are generated numerically using the obtained excitation coefficients. The results reveal that not only the ripples are controlled in the trade-in region, but also maintained sidelobe levels in the acceptable limits. The results presented are very much useful for marine radar applications.

Multi-band Monopole Antennas Loaded with Metamaterial TL

Frequenz ◽  
2015 ◽  
Vol 69 (5-6) ◽  
Author(s):  
Zhi-jie Song ◽  
Jian-gang Liang
Keyword(s):  
Transmission Line ◽  
Equivalent Circuit ◽  
Impedance Matching ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Radiation Patterns ◽  
Archimedean Spiral ◽  
Lumped Element ◽  
Monopole Antennas ◽  
Better Than

AbstractA novel metamaterial transmission line (TL) by loading complementary single Archimedean spiral resonator pair (CSASRP) is investigated and used to design a set of multi-frequency monopole antennas. The particularity is that the CSASRP which features dual-shunt branches in the equivalent circuit model is directly etched in the signal strip. By smartly controlling the element parameters, three antennas are designed and one of them covering UMTS and Bluetooth bands is fabricated and measured. The antenna exhibits impedance matching better than –10 dB and normal monopolar radiation patterns at working bands of 1.9–2.22 and 2.38–2.5 GHz. Moreover, the loaded element also contributes to the radiation, which is the major advantage of this prescription over previous lumped-element loadings. The proposed antenna is also more compact over previous designs.

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